:: Second-order Partial Differentiation of Real Ternary Functions
:: by Takao Inou\'e
::
:: Received January 26, 2010
:: Copyright (c) 2010 Association of Mizar Users


begin

definition
let f be PartFunc of (REAL 3),REAL ;
let u be Element of REAL 3;
pred f is_hpartial_differentiable`11_in u means :Def3: :: PDIFF_5:def 1
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
for x being Real st x in N holds
((SVF1 1,(pdiff1 f,1),u) . x) - ((SVF1 1,(pdiff1 f,1),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) );
pred f is_hpartial_differentiable`12_in u means :Def4: :: PDIFF_5:def 2
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
for y being Real st y in N holds
((SVF1 2,(pdiff1 f,1),u) . y) - ((SVF1 2,(pdiff1 f,1),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) );
pred f is_hpartial_differentiable`13_in u means :Def4ForZ: :: PDIFF_5:def 3
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
for z being Real st z in N holds
((SVF1 3,(pdiff1 f,1),u) . z) - ((SVF1 3,(pdiff1 f,1),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) );
pred f is_hpartial_differentiable`21_in u means :Def5: :: PDIFF_5:def 4
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
for x being Real st x in N holds
((SVF1 1,(pdiff1 f,2),u) . x) - ((SVF1 1,(pdiff1 f,2),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) );
pred f is_hpartial_differentiable`22_in u means :Def6: :: PDIFF_5:def 5
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
for y being Real st y in N holds
((SVF1 2,(pdiff1 f,2),u) . y) - ((SVF1 2,(pdiff1 f,2),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) );
pred f is_hpartial_differentiable`23_in u means :Def6ForZ: :: PDIFF_5:def 6
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
for z being Real st z in N holds
((SVF1 3,(pdiff1 f,2),u) . z) - ((SVF1 3,(pdiff1 f,2),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) );
pred f is_hpartial_differentiable`31_in u means :Def5ForSecondOrder: :: PDIFF_5:def 7
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
for x being Real st x in N holds
((SVF1 1,(pdiff1 f,3),u) . x) - ((SVF1 1,(pdiff1 f,3),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) );
pred f is_hpartial_differentiable`32_in u means :Def6ForSecondOrder: :: PDIFF_5:def 8
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
for y being Real st y in N holds
((SVF1 2,(pdiff1 f,3),u) . y) - ((SVF1 2,(pdiff1 f,3),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) );
pred f is_hpartial_differentiable`33_in u means :Def6ForZForSecondOrder: :: PDIFF_5:def 9
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
for z being Real st z in N holds
((SVF1 3,(pdiff1 f,3),u) . z) - ((SVF1 3,(pdiff1 f,3),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) );
end;

:: deftheorem Def3 defines is_hpartial_differentiable`11_in PDIFF_5:def 1 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 holds
( f is_hpartial_differentiable`11_in u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
for x being Real st x in N holds
((SVF1 1,(pdiff1 f,1),u) . x) - ((SVF1 1,(pdiff1 f,1),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) );

:: deftheorem Def4 defines is_hpartial_differentiable`12_in PDIFF_5:def 2 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 holds
( f is_hpartial_differentiable`12_in u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
for y being Real st y in N holds
((SVF1 2,(pdiff1 f,1),u) . y) - ((SVF1 2,(pdiff1 f,1),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) );

:: deftheorem Def4ForZ defines is_hpartial_differentiable`13_in PDIFF_5:def 3 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 holds
( f is_hpartial_differentiable`13_in u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
for z being Real st z in N holds
((SVF1 3,(pdiff1 f,1),u) . z) - ((SVF1 3,(pdiff1 f,1),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) );

:: deftheorem Def5 defines is_hpartial_differentiable`21_in PDIFF_5:def 4 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 holds
( f is_hpartial_differentiable`21_in u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
for x being Real st x in N holds
((SVF1 1,(pdiff1 f,2),u) . x) - ((SVF1 1,(pdiff1 f,2),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) );

:: deftheorem Def6 defines is_hpartial_differentiable`22_in PDIFF_5:def 5 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 holds
( f is_hpartial_differentiable`22_in u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
for y being Real st y in N holds
((SVF1 2,(pdiff1 f,2),u) . y) - ((SVF1 2,(pdiff1 f,2),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) );

:: deftheorem Def6ForZ defines is_hpartial_differentiable`23_in PDIFF_5:def 6 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 holds
( f is_hpartial_differentiable`23_in u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
for z being Real st z in N holds
((SVF1 3,(pdiff1 f,2),u) . z) - ((SVF1 3,(pdiff1 f,2),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) );

:: deftheorem Def5ForSecondOrder defines is_hpartial_differentiable`31_in PDIFF_5:def 7 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 holds
( f is_hpartial_differentiable`31_in u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
for x being Real st x in N holds
((SVF1 1,(pdiff1 f,3),u) . x) - ((SVF1 1,(pdiff1 f,3),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) );

:: deftheorem Def6ForSecondOrder defines is_hpartial_differentiable`32_in PDIFF_5:def 8 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 holds
( f is_hpartial_differentiable`32_in u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
for y being Real st y in N holds
((SVF1 2,(pdiff1 f,3),u) . y) - ((SVF1 2,(pdiff1 f,3),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) );

:: deftheorem Def6ForZForSecondOrder defines is_hpartial_differentiable`33_in PDIFF_5:def 9 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 holds
( f is_hpartial_differentiable`33_in u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
for z being Real st z in N holds
((SVF1 3,(pdiff1 f,3),u) . z) - ((SVF1 3,(pdiff1 f,3),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let u be Element of REAL 3;
assume A1: f is_hpartial_differentiable`11_in u ;
func hpartdiff11 f,u -> Real means :Def7: :: PDIFF_5:def 10
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( it = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,1),u) . x) - ((SVF1 1,(pdiff1 f,1),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) );
existence
ex b1, x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,1),u) . x) - ((SVF1 1,(pdiff1 f,1),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) )
proof end;
uniqueness
for b1, b2 being Real st ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,1),u) . x) - ((SVF1 1,(pdiff1 f,1),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) ) & ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( b2 = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,1),u) . x) - ((SVF1 1,(pdiff1 f,1),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def7 defines hpartdiff11 PDIFF_5:def 10 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 st f is_hpartial_differentiable`11_in u holds
for b3 being Real holds
( b3 = hpartdiff11 f,u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( b3 = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,1),u) . x) - ((SVF1 1,(pdiff1 f,1),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let u be Element of REAL 3;
assume A1: f is_hpartial_differentiable`12_in u ;
func hpartdiff12 f,u -> Real means :Def8: :: PDIFF_5:def 11
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( it = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,1),u) . y) - ((SVF1 2,(pdiff1 f,1),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) );
existence
ex b1, x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,1),u) . y) - ((SVF1 2,(pdiff1 f,1),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) )
proof end;
uniqueness
for b1, b2 being Real st ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,1),u) . y) - ((SVF1 2,(pdiff1 f,1),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) ) & ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( b2 = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,1),u) . y) - ((SVF1 2,(pdiff1 f,1),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def8 defines hpartdiff12 PDIFF_5:def 11 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 st f is_hpartial_differentiable`12_in u holds
for b3 being Real holds
( b3 = hpartdiff12 f,u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( b3 = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,1),u) . y) - ((SVF1 2,(pdiff1 f,1),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let u be Element of REAL 3;
assume A1: f is_hpartial_differentiable`13_in u ;
func hpartdiff13 f,u -> Real means :Def8ForZ: :: PDIFF_5:def 12
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( it = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,1),u) . z) - ((SVF1 3,(pdiff1 f,1),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) );
existence
ex b1, x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,1),u) . z) - ((SVF1 3,(pdiff1 f,1),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) )
proof end;
uniqueness
for b1, b2 being Real st ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,1),u) . z) - ((SVF1 3,(pdiff1 f,1),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) ) & ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( b2 = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,1),u) . z) - ((SVF1 3,(pdiff1 f,1),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def8ForZ defines hpartdiff13 PDIFF_5:def 12 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 st f is_hpartial_differentiable`13_in u holds
for b3 being Real holds
( b3 = hpartdiff13 f,u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,1),u) & ex L being LINEAR ex R being REST st
( b3 = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,1),u) . z) - ((SVF1 3,(pdiff1 f,1),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let u be Element of REAL 3;
assume A1: f is_hpartial_differentiable`21_in u ;
func hpartdiff21 f,u -> Real means :Def9: :: PDIFF_5:def 13
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( it = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,2),u) . x) - ((SVF1 1,(pdiff1 f,2),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) );
existence
ex b1, x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,2),u) . x) - ((SVF1 1,(pdiff1 f,2),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) )
proof end;
uniqueness
for b1, b2 being Real st ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,2),u) . x) - ((SVF1 1,(pdiff1 f,2),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) ) & ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( b2 = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,2),u) . x) - ((SVF1 1,(pdiff1 f,2),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def9 defines hpartdiff21 PDIFF_5:def 13 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 st f is_hpartial_differentiable`21_in u holds
for b3 being Real holds
( b3 = hpartdiff21 f,u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( b3 = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,2),u) . x) - ((SVF1 1,(pdiff1 f,2),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let u be Element of REAL 3;
assume A1: f is_hpartial_differentiable`22_in u ;
func hpartdiff22 f,u -> Real means :Def10: :: PDIFF_5:def 14
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( it = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,2),u) . y) - ((SVF1 2,(pdiff1 f,2),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) );
existence
ex b1, x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,2),u) . y) - ((SVF1 2,(pdiff1 f,2),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) )
proof end;
uniqueness
for b1, b2 being Real st ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,2),u) . y) - ((SVF1 2,(pdiff1 f,2),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) ) & ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( b2 = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,2),u) . y) - ((SVF1 2,(pdiff1 f,2),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def10 defines hpartdiff22 PDIFF_5:def 14 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 st f is_hpartial_differentiable`22_in u holds
for b3 being Real holds
( b3 = hpartdiff22 f,u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( b3 = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,2),u) . y) - ((SVF1 2,(pdiff1 f,2),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let u be Element of REAL 3;
assume A1: f is_hpartial_differentiable`23_in u ;
func hpartdiff23 f,u -> Real means :Def10ForZ: :: PDIFF_5:def 15
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( it = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,2),u) . z) - ((SVF1 3,(pdiff1 f,2),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) );
existence
ex b1, x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,2),u) . z) - ((SVF1 3,(pdiff1 f,2),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) )
proof end;
uniqueness
for b1, b2 being Real st ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,2),u) . z) - ((SVF1 3,(pdiff1 f,2),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) ) & ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( b2 = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,2),u) . z) - ((SVF1 3,(pdiff1 f,2),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def10ForZ defines hpartdiff23 PDIFF_5:def 15 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 st f is_hpartial_differentiable`23_in u holds
for b3 being Real holds
( b3 = hpartdiff23 f,u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,2),u) & ex L being LINEAR ex R being REST st
( b3 = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,2),u) . z) - ((SVF1 3,(pdiff1 f,2),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let u be Element of REAL 3;
assume A1: f is_hpartial_differentiable`31_in u ;
func hpartdiff31 f,u -> Real means :Def9ForSecondOrder: :: PDIFF_5:def 16
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( it = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,3),u) . x) - ((SVF1 1,(pdiff1 f,3),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) );
existence
ex b1, x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,3),u) . x) - ((SVF1 1,(pdiff1 f,3),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) )
proof end;
uniqueness
for b1, b2 being Real st ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,3),u) . x) - ((SVF1 1,(pdiff1 f,3),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) ) & ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( b2 = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,3),u) . x) - ((SVF1 1,(pdiff1 f,3),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def9ForSecondOrder defines hpartdiff31 PDIFF_5:def 16 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 st f is_hpartial_differentiable`31_in u holds
for b3 being Real holds
( b3 = hpartdiff31 f,u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of x0 st
( N c= dom (SVF1 1,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( b3 = L . 1 & ( for x being Real st x in N holds
((SVF1 1,(pdiff1 f,3),u) . x) - ((SVF1 1,(pdiff1 f,3),u) . x0) = (L . (x - x0)) + (R . (x - x0)) ) ) ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let u be Element of REAL 3;
assume A1: f is_hpartial_differentiable`32_in u ;
func hpartdiff32 f,u -> Real means :Def10ForSecondOrder: :: PDIFF_5:def 17
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( it = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,3),u) . y) - ((SVF1 2,(pdiff1 f,3),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) );
existence
ex b1, x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,3),u) . y) - ((SVF1 2,(pdiff1 f,3),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) )
proof end;
uniqueness
for b1, b2 being Real st ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,3),u) . y) - ((SVF1 2,(pdiff1 f,3),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) ) & ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( b2 = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,3),u) . y) - ((SVF1 2,(pdiff1 f,3),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def10ForSecondOrder defines hpartdiff32 PDIFF_5:def 17 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 st f is_hpartial_differentiable`32_in u holds
for b3 being Real holds
( b3 = hpartdiff32 f,u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of y0 st
( N c= dom (SVF1 2,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( b3 = L . 1 & ( for y being Real st y in N holds
((SVF1 2,(pdiff1 f,3),u) . y) - ((SVF1 2,(pdiff1 f,3),u) . y0) = (L . (y - y0)) + (R . (y - y0)) ) ) ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let u be Element of REAL 3;
assume A1: f is_hpartial_differentiable`33_in u ;
func hpartdiff33 f,u -> Real means :Def10ForZForSecondOrder: :: PDIFF_5:def 18
ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( it = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,3),u) . z) - ((SVF1 3,(pdiff1 f,3),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) );
existence
ex b1, x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,3),u) . z) - ((SVF1 3,(pdiff1 f,3),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) )
proof end;
uniqueness
for b1, b2 being Real st ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( b1 = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,3),u) . z) - ((SVF1 3,(pdiff1 f,3),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) ) & ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( b2 = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,3),u) . z) - ((SVF1 3,(pdiff1 f,3),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def10ForZForSecondOrder defines hpartdiff33 PDIFF_5:def 18 :
for f being PartFunc of (REAL 3),REAL
for u being Element of REAL 3 st f is_hpartial_differentiable`33_in u holds
for b3 being Real holds
( b3 = hpartdiff33 f,u iff ex x0, y0, z0 being Real st
( u = <*x0,y0,z0*> & ex N being Neighbourhood of z0 st
( N c= dom (SVF1 3,(pdiff1 f,3),u) & ex L being LINEAR ex R being REST st
( b3 = L . 1 & ( for z being Real st z in N holds
((SVF1 3,(pdiff1 f,3),u) . z) - ((SVF1 3,(pdiff1 f,3),u) . z0) = (L . (z - z0)) + (R . (z - z0)) ) ) ) ) );

theorem :: PDIFF_5:1
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`11_in u holds
SVF1 1,(pdiff1 f,1),u is_differentiable_in x0
proof end;

theorem :: PDIFF_5:2
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`12_in u holds
SVF1 2,(pdiff1 f,1),u is_differentiable_in y0
proof end;

theorem :: PDIFF_5:3
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`13_in u holds
SVF1 3,(pdiff1 f,1),u is_differentiable_in z0
proof end;

theorem :: PDIFF_5:4
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`21_in u holds
SVF1 1,(pdiff1 f,2),u is_differentiable_in x0
proof end;

theorem :: PDIFF_5:5
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`22_in u holds
SVF1 2,(pdiff1 f,2),u is_differentiable_in y0
proof end;

theorem :: PDIFF_5:6
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`23_in u holds
SVF1 3,(pdiff1 f,2),u is_differentiable_in z0
proof end;

theorem :: PDIFF_5:7
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`31_in u holds
SVF1 1,(pdiff1 f,3),u is_differentiable_in x0
proof end;

theorem :: PDIFF_5:8
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`32_in u holds
SVF1 2,(pdiff1 f,3),u is_differentiable_in y0
proof end;

theorem :: PDIFF_5:9
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`33_in u holds
SVF1 3,(pdiff1 f,3),u is_differentiable_in z0
proof end;

theorem Th5: :: PDIFF_5:10
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`11_in u holds
hpartdiff11 f,u = diff (SVF1 1,(pdiff1 f,1),u),x0
proof end;

theorem Th6: :: PDIFF_5:11
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`12_in u holds
hpartdiff12 f,u = diff (SVF1 2,(pdiff1 f,1),u),y0
proof end;

theorem Th6ForZ: :: PDIFF_5:12
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`13_in u holds
hpartdiff13 f,u = diff (SVF1 3,(pdiff1 f,1),u),z0
proof end;

theorem Th7: :: PDIFF_5:13
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`21_in u holds
hpartdiff21 f,u = diff (SVF1 1,(pdiff1 f,2),u),x0
proof end;

theorem Th8: :: PDIFF_5:14
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`22_in u holds
hpartdiff22 f,u = diff (SVF1 2,(pdiff1 f,2),u),y0
proof end;

theorem Th8ForZ: :: PDIFF_5:15
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`23_in u holds
hpartdiff23 f,u = diff (SVF1 3,(pdiff1 f,2),u),z0
proof end;

theorem Th7ForSecondOrder: :: PDIFF_5:16
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`31_in u holds
hpartdiff31 f,u = diff (SVF1 1,(pdiff1 f,3),u),x0
proof end;

theorem Th8ForSecondOrder: :: PDIFF_5:17
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`32_in u holds
hpartdiff32 f,u = diff (SVF1 2,(pdiff1 f,3),u),y0
proof end;

theorem Th8ForZForSecondOrder: :: PDIFF_5:18
for x0, y0, z0 being Real
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st u = <*x0,y0,z0*> & f is_hpartial_differentiable`33_in u holds
hpartdiff33 f,u = diff (SVF1 3,(pdiff1 f,3),u),z0
proof end;

definition
let f be PartFunc of (REAL 3),REAL ;
let D be set ;
pred f is_hpartial_differentiable`11_on D means :Def11: :: PDIFF_5:def 19
( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`11_in u ) );
pred f is_hpartial_differentiable`12_on D means :Def12: :: PDIFF_5:def 20
( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`12_in u ) );
pred f is_hpartial_differentiable`13_on D means :Def12ForZ: :: PDIFF_5:def 21
( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`13_in u ) );
pred f is_hpartial_differentiable`21_on D means :Def13: :: PDIFF_5:def 22
( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`21_in u ) );
pred f is_hpartial_differentiable`22_on D means :Def14: :: PDIFF_5:def 23
( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`22_in u ) );
pred f is_hpartial_differentiable`23_on D means :Def14ForZ: :: PDIFF_5:def 24
( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`23_in u ) );
pred f is_hpartial_differentiable`31_on D means :Def13ForSecondOrder: :: PDIFF_5:def 25
( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`31_in u ) );
pred f is_hpartial_differentiable`32_on D means :Def14ForSecondOrder: :: PDIFF_5:def 26
( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`32_in u ) );
pred f is_hpartial_differentiable`33_on D means :Def14ForZForSecondOrder: :: PDIFF_5:def 27
( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`33_in u ) );
end;

:: deftheorem Def11 defines is_hpartial_differentiable`11_on PDIFF_5:def 19 :
for f being PartFunc of (REAL 3),REAL
for D being set holds
( f is_hpartial_differentiable`11_on D iff ( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`11_in u ) ) );

:: deftheorem Def12 defines is_hpartial_differentiable`12_on PDIFF_5:def 20 :
for f being PartFunc of (REAL 3),REAL
for D being set holds
( f is_hpartial_differentiable`12_on D iff ( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`12_in u ) ) );

:: deftheorem Def12ForZ defines is_hpartial_differentiable`13_on PDIFF_5:def 21 :
for f being PartFunc of (REAL 3),REAL
for D being set holds
( f is_hpartial_differentiable`13_on D iff ( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`13_in u ) ) );

:: deftheorem Def13 defines is_hpartial_differentiable`21_on PDIFF_5:def 22 :
for f being PartFunc of (REAL 3),REAL
for D being set holds
( f is_hpartial_differentiable`21_on D iff ( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`21_in u ) ) );

:: deftheorem Def14 defines is_hpartial_differentiable`22_on PDIFF_5:def 23 :
for f being PartFunc of (REAL 3),REAL
for D being set holds
( f is_hpartial_differentiable`22_on D iff ( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`22_in u ) ) );

:: deftheorem Def14ForZ defines is_hpartial_differentiable`23_on PDIFF_5:def 24 :
for f being PartFunc of (REAL 3),REAL
for D being set holds
( f is_hpartial_differentiable`23_on D iff ( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`23_in u ) ) );

:: deftheorem Def13ForSecondOrder defines is_hpartial_differentiable`31_on PDIFF_5:def 25 :
for f being PartFunc of (REAL 3),REAL
for D being set holds
( f is_hpartial_differentiable`31_on D iff ( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`31_in u ) ) );

:: deftheorem Def14ForSecondOrder defines is_hpartial_differentiable`32_on PDIFF_5:def 26 :
for f being PartFunc of (REAL 3),REAL
for D being set holds
( f is_hpartial_differentiable`32_on D iff ( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`32_in u ) ) );

:: deftheorem Def14ForZForSecondOrder defines is_hpartial_differentiable`33_on PDIFF_5:def 27 :
for f being PartFunc of (REAL 3),REAL
for D being set holds
( f is_hpartial_differentiable`33_on D iff ( D c= dom f & ( for u being Element of REAL 3 st u in D holds
f | D is_hpartial_differentiable`33_in u ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let D be set ;
assume A1: f is_hpartial_differentiable`11_on D ;
func f `hpartial11| D -> PartFunc of (REAL 3),REAL means :: PDIFF_5:def 28
( dom it = D & ( for u being Element of REAL 3 st u in D holds
it . u = hpartdiff11 f,u ) );
existence
ex b1 being PartFunc of (REAL 3),REAL st
( dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff11 f,u ) )
proof end;
uniqueness
for b1, b2 being PartFunc of (REAL 3),REAL st dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff11 f,u ) & dom b2 = D & ( for u being Element of REAL 3 st u in D holds
b2 . u = hpartdiff11 f,u ) holds
b1 = b2
proof end;
end;

:: deftheorem defines `hpartial11| PDIFF_5:def 28 :
for f being PartFunc of (REAL 3),REAL
for D being set st f is_hpartial_differentiable`11_on D holds
for b3 being PartFunc of (REAL 3),REAL holds
( b3 = f `hpartial11| D iff ( dom b3 = D & ( for u being Element of REAL 3 st u in D holds
b3 . u = hpartdiff11 f,u ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let D be set ;
assume A1: f is_hpartial_differentiable`12_on D ;
func f `hpartial12| D -> PartFunc of (REAL 3),REAL means :: PDIFF_5:def 29
( dom it = D & ( for u being Element of REAL 3 st u in D holds
it . u = hpartdiff12 f,u ) );
existence
ex b1 being PartFunc of (REAL 3),REAL st
( dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff12 f,u ) )
proof end;
uniqueness
for b1, b2 being PartFunc of (REAL 3),REAL st dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff12 f,u ) & dom b2 = D & ( for u being Element of REAL 3 st u in D holds
b2 . u = hpartdiff12 f,u ) holds
b1 = b2
proof end;
end;

:: deftheorem defines `hpartial12| PDIFF_5:def 29 :
for f being PartFunc of (REAL 3),REAL
for D being set st f is_hpartial_differentiable`12_on D holds
for b3 being PartFunc of (REAL 3),REAL holds
( b3 = f `hpartial12| D iff ( dom b3 = D & ( for u being Element of REAL 3 st u in D holds
b3 . u = hpartdiff12 f,u ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let D be set ;
assume A1: f is_hpartial_differentiable`13_on D ;
func f `hpartial13| D -> PartFunc of (REAL 3),REAL means :: PDIFF_5:def 30
( dom it = D & ( for u being Element of REAL 3 st u in D holds
it . u = hpartdiff13 f,u ) );
existence
ex b1 being PartFunc of (REAL 3),REAL st
( dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff13 f,u ) )
proof end;
uniqueness
for b1, b2 being PartFunc of (REAL 3),REAL st dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff13 f,u ) & dom b2 = D & ( for u being Element of REAL 3 st u in D holds
b2 . u = hpartdiff13 f,u ) holds
b1 = b2
proof end;
end;

:: deftheorem defines `hpartial13| PDIFF_5:def 30 :
for f being PartFunc of (REAL 3),REAL
for D being set st f is_hpartial_differentiable`13_on D holds
for b3 being PartFunc of (REAL 3),REAL holds
( b3 = f `hpartial13| D iff ( dom b3 = D & ( for u being Element of REAL 3 st u in D holds
b3 . u = hpartdiff13 f,u ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let D be set ;
assume A1: f is_hpartial_differentiable`21_on D ;
func f `hpartial21| D -> PartFunc of (REAL 3),REAL means :: PDIFF_5:def 31
( dom it = D & ( for u being Element of REAL 3 st u in D holds
it . u = hpartdiff21 f,u ) );
existence
ex b1 being PartFunc of (REAL 3),REAL st
( dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff21 f,u ) )
proof end;
uniqueness
for b1, b2 being PartFunc of (REAL 3),REAL st dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff21 f,u ) & dom b2 = D & ( for u being Element of REAL 3 st u in D holds
b2 . u = hpartdiff21 f,u ) holds
b1 = b2
proof end;
end;

:: deftheorem defines `hpartial21| PDIFF_5:def 31 :
for f being PartFunc of (REAL 3),REAL
for D being set st f is_hpartial_differentiable`21_on D holds
for b3 being PartFunc of (REAL 3),REAL holds
( b3 = f `hpartial21| D iff ( dom b3 = D & ( for u being Element of REAL 3 st u in D holds
b3 . u = hpartdiff21 f,u ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let D be set ;
assume A1: f is_hpartial_differentiable`22_on D ;
func f `hpartial22| D -> PartFunc of (REAL 3),REAL means :: PDIFF_5:def 32
( dom it = D & ( for u being Element of REAL 3 st u in D holds
it . u = hpartdiff22 f,u ) );
existence
ex b1 being PartFunc of (REAL 3),REAL st
( dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff22 f,u ) )
proof end;
uniqueness
for b1, b2 being PartFunc of (REAL 3),REAL st dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff22 f,u ) & dom b2 = D & ( for u being Element of REAL 3 st u in D holds
b2 . u = hpartdiff22 f,u ) holds
b1 = b2
proof end;
end;

:: deftheorem defines `hpartial22| PDIFF_5:def 32 :
for f being PartFunc of (REAL 3),REAL
for D being set st f is_hpartial_differentiable`22_on D holds
for b3 being PartFunc of (REAL 3),REAL holds
( b3 = f `hpartial22| D iff ( dom b3 = D & ( for u being Element of REAL 3 st u in D holds
b3 . u = hpartdiff22 f,u ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let D be set ;
assume A1: f is_hpartial_differentiable`23_on D ;
func f `hpartial23| D -> PartFunc of (REAL 3),REAL means :: PDIFF_5:def 33
( dom it = D & ( for u being Element of REAL 3 st u in D holds
it . u = hpartdiff23 f,u ) );
existence
ex b1 being PartFunc of (REAL 3),REAL st
( dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff23 f,u ) )
proof end;
uniqueness
for b1, b2 being PartFunc of (REAL 3),REAL st dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff23 f,u ) & dom b2 = D & ( for u being Element of REAL 3 st u in D holds
b2 . u = hpartdiff23 f,u ) holds
b1 = b2
proof end;
end;

:: deftheorem defines `hpartial23| PDIFF_5:def 33 :
for f being PartFunc of (REAL 3),REAL
for D being set st f is_hpartial_differentiable`23_on D holds
for b3 being PartFunc of (REAL 3),REAL holds
( b3 = f `hpartial23| D iff ( dom b3 = D & ( for u being Element of REAL 3 st u in D holds
b3 . u = hpartdiff23 f,u ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let D be set ;
assume A1: f is_hpartial_differentiable`31_on D ;
func f `hpartial31| D -> PartFunc of (REAL 3),REAL means :: PDIFF_5:def 34
( dom it = D & ( for u being Element of REAL 3 st u in D holds
it . u = hpartdiff31 f,u ) );
existence
ex b1 being PartFunc of (REAL 3),REAL st
( dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff31 f,u ) )
proof end;
uniqueness
for b1, b2 being PartFunc of (REAL 3),REAL st dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff31 f,u ) & dom b2 = D & ( for u being Element of REAL 3 st u in D holds
b2 . u = hpartdiff31 f,u ) holds
b1 = b2
proof end;
end;

:: deftheorem defines `hpartial31| PDIFF_5:def 34 :
for f being PartFunc of (REAL 3),REAL
for D being set st f is_hpartial_differentiable`31_on D holds
for b3 being PartFunc of (REAL 3),REAL holds
( b3 = f `hpartial31| D iff ( dom b3 = D & ( for u being Element of REAL 3 st u in D holds
b3 . u = hpartdiff31 f,u ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let D be set ;
assume A1: f is_hpartial_differentiable`32_on D ;
func f `hpartial32| D -> PartFunc of (REAL 3),REAL means :: PDIFF_5:def 35
( dom it = D & ( for u being Element of REAL 3 st u in D holds
it . u = hpartdiff32 f,u ) );
existence
ex b1 being PartFunc of (REAL 3),REAL st
( dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff32 f,u ) )
proof end;
uniqueness
for b1, b2 being PartFunc of (REAL 3),REAL st dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff32 f,u ) & dom b2 = D & ( for u being Element of REAL 3 st u in D holds
b2 . u = hpartdiff32 f,u ) holds
b1 = b2
proof end;
end;

:: deftheorem defines `hpartial32| PDIFF_5:def 35 :
for f being PartFunc of (REAL 3),REAL
for D being set st f is_hpartial_differentiable`32_on D holds
for b3 being PartFunc of (REAL 3),REAL holds
( b3 = f `hpartial32| D iff ( dom b3 = D & ( for u being Element of REAL 3 st u in D holds
b3 . u = hpartdiff32 f,u ) ) );

definition
let f be PartFunc of (REAL 3),REAL ;
let D be set ;
assume A1: f is_hpartial_differentiable`33_on D ;
func f `hpartial33| D -> PartFunc of (REAL 3),REAL means :: PDIFF_5:def 36
( dom it = D & ( for u being Element of REAL 3 st u in D holds
it . u = hpartdiff33 f,u ) );
existence
ex b1 being PartFunc of (REAL 3),REAL st
( dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff33 f,u ) )
proof end;
uniqueness
for b1, b2 being PartFunc of (REAL 3),REAL st dom b1 = D & ( for u being Element of REAL 3 st u in D holds
b1 . u = hpartdiff33 f,u ) & dom b2 = D & ( for u being Element of REAL 3 st u in D holds
b2 . u = hpartdiff33 f,u ) holds
b1 = b2
proof end;
end;

:: deftheorem defines `hpartial33| PDIFF_5:def 36 :
for f being PartFunc of (REAL 3),REAL
for D being set st f is_hpartial_differentiable`33_on D holds
for b3 being PartFunc of (REAL 3),REAL holds
( b3 = f `hpartial33| D iff ( dom b3 = D & ( for u being Element of REAL 3 st u in D holds
b3 . u = hpartdiff33 f,u ) ) );

begin

theorem Th9: :: PDIFF_5:19
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL holds
( f is_hpartial_differentiable`11_in u iff pdiff1 f,1 is_partial_differentiable_in u,1 )
proof end;

theorem Th10: :: PDIFF_5:20
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL holds
( f is_hpartial_differentiable`12_in u iff pdiff1 f,1 is_partial_differentiable_in u,2 )
proof end;

theorem Th10ForZ: :: PDIFF_5:21
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL holds
( f is_hpartial_differentiable`13_in u iff pdiff1 f,1 is_partial_differentiable_in u,3 )
proof end;

theorem Th11: :: PDIFF_5:22
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL holds
( f is_hpartial_differentiable`21_in u iff pdiff1 f,2 is_partial_differentiable_in u,1 )
proof end;

theorem Th12: :: PDIFF_5:23
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL holds
( f is_hpartial_differentiable`22_in u iff pdiff1 f,2 is_partial_differentiable_in u,2 )
proof end;

theorem Th12ForZ: :: PDIFF_5:24
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL holds
( f is_hpartial_differentiable`23_in u iff pdiff1 f,2 is_partial_differentiable_in u,3 )
proof end;

theorem Th11ForSecondOrder: :: PDIFF_5:25
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL holds
( f is_hpartial_differentiable`31_in u iff pdiff1 f,3 is_partial_differentiable_in u,1 )
proof end;

theorem Th12ForSecondOrder: :: PDIFF_5:26
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL holds
( f is_hpartial_differentiable`32_in u iff pdiff1 f,3 is_partial_differentiable_in u,2 )
proof end;

theorem Th12ForZForSecondOrder: :: PDIFF_5:27
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL holds
( f is_hpartial_differentiable`33_in u iff pdiff1 f,3 is_partial_differentiable_in u,3 )
proof end;

theorem Th17: :: PDIFF_5:28
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`11_in u holds
hpartdiff11 f,u = partdiff (pdiff1 f,1),u,1
proof end;

theorem Th18: :: PDIFF_5:29
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`12_in u holds
hpartdiff12 f,u = partdiff (pdiff1 f,1),u,2
proof end;

theorem Th18ForZ: :: PDIFF_5:30
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`13_in u holds
hpartdiff13 f,u = partdiff (pdiff1 f,1),u,3
proof end;

theorem Th19: :: PDIFF_5:31
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`21_in u holds
hpartdiff21 f,u = partdiff (pdiff1 f,2),u,1
proof end;

theorem Th20: :: PDIFF_5:32
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`22_in u holds
hpartdiff22 f,u = partdiff (pdiff1 f,2),u,2
proof end;

theorem Th20ForZ: :: PDIFF_5:33
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`23_in u holds
hpartdiff23 f,u = partdiff (pdiff1 f,2),u,3
proof end;

theorem Th19ForSecondOrder: :: PDIFF_5:34
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`31_in u holds
hpartdiff31 f,u = partdiff (pdiff1 f,3),u,1
proof end;

theorem Th20ForSecondOrder: :: PDIFF_5:35
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`32_in u holds
hpartdiff32 f,u = partdiff (pdiff1 f,3),u,2
proof end;

theorem Th20ForZForSecondOrder: :: PDIFF_5:36
for u being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`33_in u holds
hpartdiff33 f,u = partdiff (pdiff1 f,3),u,3
proof end;

theorem :: PDIFF_5:37
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3
for N being Neighbourhood of (proj 1,3) . u0 st f is_hpartial_differentiable`11_in u0 & N c= dom (SVF1 1,(pdiff1 f,1),u0) holds
for h being convergent_to_0 Real_Sequence
for c being V20() Real_Sequence st rng c = {((proj 1,3) . u0)} & rng (h + c) c= N holds
( (h " ) (#) (((SVF1 1,(pdiff1 f,1),u0) /* (h + c)) - ((SVF1 1,(pdiff1 f,1),u0) /* c)) is convergent & hpartdiff11 f,u0 = lim ((h " ) (#) (((SVF1 1,(pdiff1 f,1),u0) /* (h + c)) - ((SVF1 1,(pdiff1 f,1),u0) /* c))) )
proof end;

theorem :: PDIFF_5:38
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3
for N being Neighbourhood of (proj 2,3) . u0 st f is_hpartial_differentiable`12_in u0 & N c= dom (SVF1 2,(pdiff1 f,1),u0) holds
for h being convergent_to_0 Real_Sequence
for c being V20() Real_Sequence st rng c = {((proj 2,3) . u0)} & rng (h + c) c= N holds
( (h " ) (#) (((SVF1 2,(pdiff1 f,1),u0) /* (h + c)) - ((SVF1 2,(pdiff1 f,1),u0) /* c)) is convergent & hpartdiff12 f,u0 = lim ((h " ) (#) (((SVF1 2,(pdiff1 f,1),u0) /* (h + c)) - ((SVF1 2,(pdiff1 f,1),u0) /* c))) )
proof end;

theorem :: PDIFF_5:39
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3
for N being Neighbourhood of (proj 3,3) . u0 st f is_hpartial_differentiable`13_in u0 & N c= dom (SVF1 3,(pdiff1 f,1),u0) holds
for h being convergent_to_0 Real_Sequence
for c being V20() Real_Sequence st rng c = {((proj 3,3) . u0)} & rng (h + c) c= N holds
( (h " ) (#) (((SVF1 3,(pdiff1 f,1),u0) /* (h + c)) - ((SVF1 3,(pdiff1 f,1),u0) /* c)) is convergent & hpartdiff13 f,u0 = lim ((h " ) (#) (((SVF1 3,(pdiff1 f,1),u0) /* (h + c)) - ((SVF1 3,(pdiff1 f,1),u0) /* c))) )
proof end;

theorem :: PDIFF_5:40
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3
for N being Neighbourhood of (proj 1,3) . u0 st f is_hpartial_differentiable`21_in u0 & N c= dom (SVF1 1,(pdiff1 f,2),u0) holds
for h being convergent_to_0 Real_Sequence
for c being V20() Real_Sequence st rng c = {((proj 1,3) . u0)} & rng (h + c) c= N holds
( (h " ) (#) (((SVF1 1,(pdiff1 f,2),u0) /* (h + c)) - ((SVF1 1,(pdiff1 f,2),u0) /* c)) is convergent & hpartdiff21 f,u0 = lim ((h " ) (#) (((SVF1 1,(pdiff1 f,2),u0) /* (h + c)) - ((SVF1 1,(pdiff1 f,2),u0) /* c))) )
proof end;

theorem :: PDIFF_5:41
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3
for N being Neighbourhood of (proj 2,3) . u0 st f is_hpartial_differentiable`22_in u0 & N c= dom (SVF1 2,(pdiff1 f,2),u0) holds
for h being convergent_to_0 Real_Sequence
for c being V20() Real_Sequence st rng c = {((proj 2,3) . u0)} & rng (h + c) c= N holds
( (h " ) (#) (((SVF1 2,(pdiff1 f,2),u0) /* (h + c)) - ((SVF1 2,(pdiff1 f,2),u0) /* c)) is convergent & hpartdiff22 f,u0 = lim ((h " ) (#) (((SVF1 2,(pdiff1 f,2),u0) /* (h + c)) - ((SVF1 2,(pdiff1 f,2),u0) /* c))) )
proof end;

theorem :: PDIFF_5:42
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3
for N being Neighbourhood of (proj 3,3) . u0 st f is_hpartial_differentiable`23_in u0 & N c= dom (SVF1 3,(pdiff1 f,2),u0) holds
for h being convergent_to_0 Real_Sequence
for c being V20() Real_Sequence st rng c = {((proj 3,3) . u0)} & rng (h + c) c= N holds
( (h " ) (#) (((SVF1 3,(pdiff1 f,2),u0) /* (h + c)) - ((SVF1 3,(pdiff1 f,2),u0) /* c)) is convergent & hpartdiff23 f,u0 = lim ((h " ) (#) (((SVF1 3,(pdiff1 f,2),u0) /* (h + c)) - ((SVF1 3,(pdiff1 f,2),u0) /* c))) )
proof end;

theorem :: PDIFF_5:43
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3
for N being Neighbourhood of (proj 1,3) . u0 st f is_hpartial_differentiable`31_in u0 & N c= dom (SVF1 1,(pdiff1 f,3),u0) holds
for h being convergent_to_0 Real_Sequence
for c being V20() Real_Sequence st rng c = {((proj 1,3) . u0)} & rng (h + c) c= N holds
( (h " ) (#) (((SVF1 1,(pdiff1 f,3),u0) /* (h + c)) - ((SVF1 1,(pdiff1 f,3),u0) /* c)) is convergent & hpartdiff31 f,u0 = lim ((h " ) (#) (((SVF1 1,(pdiff1 f,3),u0) /* (h + c)) - ((SVF1 1,(pdiff1 f,3),u0) /* c))) )
proof end;

theorem :: PDIFF_5:44
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3
for N being Neighbourhood of (proj 2,3) . u0 st f is_hpartial_differentiable`32_in u0 & N c= dom (SVF1 2,(pdiff1 f,3),u0) holds
for h being convergent_to_0 Real_Sequence
for c being V20() Real_Sequence st rng c = {((proj 2,3) . u0)} & rng (h + c) c= N holds
( (h " ) (#) (((SVF1 2,(pdiff1 f,3),u0) /* (h + c)) - ((SVF1 2,(pdiff1 f,3),u0) /* c)) is convergent & hpartdiff32 f,u0 = lim ((h " ) (#) (((SVF1 2,(pdiff1 f,3),u0) /* (h + c)) - ((SVF1 2,(pdiff1 f,3),u0) /* c))) )
proof end;

theorem :: PDIFF_5:45
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3
for N being Neighbourhood of (proj 3,3) . u0 st f is_hpartial_differentiable`33_in u0 & N c= dom (SVF1 3,(pdiff1 f,3),u0) holds
for h being convergent_to_0 Real_Sequence
for c being V20() Real_Sequence st rng c = {((proj 3,3) . u0)} & rng (h + c) c= N holds
( (h " ) (#) (((SVF1 3,(pdiff1 f,3),u0) /* (h + c)) - ((SVF1 3,(pdiff1 f,3),u0) /* c)) is convergent & hpartdiff33 f,u0 = lim ((h " ) (#) (((SVF1 3,(pdiff1 f,3),u0) /* (h + c)) - ((SVF1 3,(pdiff1 f,3),u0) /* c))) )
proof end;

theorem :: PDIFF_5:46
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`11_in u0 & f2 is_hpartial_differentiable`11_in u0 holds
( (pdiff1 f1,1) + (pdiff1 f2,1) is_partial_differentiable_in u0,1 & partdiff ((pdiff1 f1,1) + (pdiff1 f2,1)),u0,1 = (hpartdiff11 f1,u0) + (hpartdiff11 f2,u0) )
proof end;

theorem :: PDIFF_5:47
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`12_in u0 & f2 is_hpartial_differentiable`12_in u0 holds
( (pdiff1 f1,1) + (pdiff1 f2,1) is_partial_differentiable_in u0,2 & partdiff ((pdiff1 f1,1) + (pdiff1 f2,1)),u0,2 = (hpartdiff12 f1,u0) + (hpartdiff12 f2,u0) )
proof end;

theorem :: PDIFF_5:48
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`13_in u0 & f2 is_hpartial_differentiable`13_in u0 holds
( (pdiff1 f1,1) + (pdiff1 f2,1) is_partial_differentiable_in u0,3 & partdiff ((pdiff1 f1,1) + (pdiff1 f2,1)),u0,3 = (hpartdiff13 f1,u0) + (hpartdiff13 f2,u0) )
proof end;

theorem :: PDIFF_5:49
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`21_in u0 & f2 is_hpartial_differentiable`21_in u0 holds
( (pdiff1 f1,2) + (pdiff1 f2,2) is_partial_differentiable_in u0,1 & partdiff ((pdiff1 f1,2) + (pdiff1 f2,2)),u0,1 = (hpartdiff21 f1,u0) + (hpartdiff21 f2,u0) )
proof end;

theorem :: PDIFF_5:50
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`22_in u0 & f2 is_hpartial_differentiable`22_in u0 holds
( (pdiff1 f1,2) + (pdiff1 f2,2) is_partial_differentiable_in u0,2 & partdiff ((pdiff1 f1,2) + (pdiff1 f2,2)),u0,2 = (hpartdiff22 f1,u0) + (hpartdiff22 f2,u0) )
proof end;

theorem :: PDIFF_5:51
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`23_in u0 & f2 is_hpartial_differentiable`23_in u0 holds
( (pdiff1 f1,2) + (pdiff1 f2,2) is_partial_differentiable_in u0,3 & partdiff ((pdiff1 f1,2) + (pdiff1 f2,2)),u0,3 = (hpartdiff23 f1,u0) + (hpartdiff23 f2,u0) )
proof end;

theorem :: PDIFF_5:52
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`11_in u0 & f2 is_hpartial_differentiable`11_in u0 holds
( (pdiff1 f1,1) - (pdiff1 f2,1) is_partial_differentiable_in u0,1 & partdiff ((pdiff1 f1,1) - (pdiff1 f2,1)),u0,1 = (hpartdiff11 f1,u0) - (hpartdiff11 f2,u0) )
proof end;

theorem :: PDIFF_5:53
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`12_in u0 & f2 is_hpartial_differentiable`12_in u0 holds
( (pdiff1 f1,1) - (pdiff1 f2,1) is_partial_differentiable_in u0,2 & partdiff ((pdiff1 f1,1) - (pdiff1 f2,1)),u0,2 = (hpartdiff12 f1,u0) - (hpartdiff12 f2,u0) )
proof end;

theorem :: PDIFF_5:54
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`13_in u0 & f2 is_hpartial_differentiable`13_in u0 holds
( (pdiff1 f1,1) - (pdiff1 f2,1) is_partial_differentiable_in u0,3 & partdiff ((pdiff1 f1,1) - (pdiff1 f2,1)),u0,3 = (hpartdiff13 f1,u0) - (hpartdiff13 f2,u0) )
proof end;

theorem :: PDIFF_5:55
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`21_in u0 & f2 is_hpartial_differentiable`21_in u0 holds
( (pdiff1 f1,2) - (pdiff1 f2,2) is_partial_differentiable_in u0,1 & partdiff ((pdiff1 f1,2) - (pdiff1 f2,2)),u0,1 = (hpartdiff21 f1,u0) - (hpartdiff21 f2,u0) )
proof end;

theorem :: PDIFF_5:56
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`22_in u0 & f2 is_hpartial_differentiable`22_in u0 holds
( (pdiff1 f1,2) - (pdiff1 f2,2) is_partial_differentiable_in u0,2 & partdiff ((pdiff1 f1,2) - (pdiff1 f2,2)),u0,2 = (hpartdiff22 f1,u0) - (hpartdiff22 f2,u0) )
proof end;

theorem :: PDIFF_5:57
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`23_in u0 & f2 is_hpartial_differentiable`23_in u0 holds
( (pdiff1 f1,2) - (pdiff1 f2,2) is_partial_differentiable_in u0,3 & partdiff ((pdiff1 f1,2) - (pdiff1 f2,2)),u0,3 = (hpartdiff23 f1,u0) - (hpartdiff23 f2,u0) )
proof end;

theorem :: PDIFF_5:58
for r being Real
for u0 being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`11_in u0 holds
( r (#) (pdiff1 f,1) is_partial_differentiable_in u0,1 & partdiff (r (#) (pdiff1 f,1)),u0,1 = r * (hpartdiff11 f,u0) )
proof end;

theorem :: PDIFF_5:59
for r being Real
for u0 being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`12_in u0 holds
( r (#) (pdiff1 f,1) is_partial_differentiable_in u0,2 & partdiff (r (#) (pdiff1 f,1)),u0,2 = r * (hpartdiff12 f,u0) )
proof end;

theorem :: PDIFF_5:60
for r being Real
for u0 being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`13_in u0 holds
( r (#) (pdiff1 f,1) is_partial_differentiable_in u0,3 & partdiff (r (#) (pdiff1 f,1)),u0,3 = r * (hpartdiff13 f,u0) )
proof end;

theorem :: PDIFF_5:61
for r being Real
for u0 being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`21_in u0 holds
( r (#) (pdiff1 f,2) is_partial_differentiable_in u0,1 & partdiff (r (#) (pdiff1 f,2)),u0,1 = r * (hpartdiff21 f,u0) )
proof end;

theorem :: PDIFF_5:62
for r being Real
for u0 being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`22_in u0 holds
( r (#) (pdiff1 f,2) is_partial_differentiable_in u0,2 & partdiff (r (#) (pdiff1 f,2)),u0,2 = r * (hpartdiff22 f,u0) )
proof end;

theorem :: PDIFF_5:63
for r being Real
for u0 being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`23_in u0 holds
( r (#) (pdiff1 f,2) is_partial_differentiable_in u0,3 & partdiff (r (#) (pdiff1 f,2)),u0,3 = r * (hpartdiff23 f,u0) )
proof end;

theorem :: PDIFF_5:64
for r being Real
for u0 being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`31_in u0 holds
( r (#) (pdiff1 f,3) is_partial_differentiable_in u0,1 & partdiff (r (#) (pdiff1 f,3)),u0,1 = r * (hpartdiff31 f,u0) )
proof end;

theorem :: PDIFF_5:65
for r being Real
for u0 being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`32_in u0 holds
( r (#) (pdiff1 f,3) is_partial_differentiable_in u0,2 & partdiff (r (#) (pdiff1 f,3)),u0,2 = r * (hpartdiff32 f,u0) )
proof end;

theorem :: PDIFF_5:66
for r being Real
for u0 being Element of REAL 3
for f being PartFunc of (REAL 3),REAL st f is_hpartial_differentiable`33_in u0 holds
( r (#) (pdiff1 f,3) is_partial_differentiable_in u0,3 & partdiff (r (#) (pdiff1 f,3)),u0,3 = r * (hpartdiff33 f,u0) )
proof end;

theorem :: PDIFF_5:67
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`11_in u0 & f2 is_hpartial_differentiable`11_in u0 holds
(pdiff1 f1,1) (#) (pdiff1 f2,1) is_partial_differentiable_in u0,1
proof end;

theorem :: PDIFF_5:68
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`12_in u0 & f2 is_hpartial_differentiable`12_in u0 holds
(pdiff1 f1,1) (#) (pdiff1 f2,1) is_partial_differentiable_in u0,2
proof end;

theorem :: PDIFF_5:69
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`13_in u0 & f2 is_hpartial_differentiable`13_in u0 holds
(pdiff1 f1,1) (#) (pdiff1 f2,1) is_partial_differentiable_in u0,3
proof end;

theorem :: PDIFF_5:70
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`21_in u0 & f2 is_hpartial_differentiable`21_in u0 holds
(pdiff1 f1,2) (#) (pdiff1 f2,2) is_partial_differentiable_in u0,1
proof end;

theorem :: PDIFF_5:71
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`22_in u0 & f2 is_hpartial_differentiable`22_in u0 holds
(pdiff1 f1,2) (#) (pdiff1 f2,2) is_partial_differentiable_in u0,2
proof end;

theorem :: PDIFF_5:72
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`23_in u0 & f2 is_hpartial_differentiable`23_in u0 holds
(pdiff1 f1,2) (#) (pdiff1 f2,2) is_partial_differentiable_in u0,3
proof end;

theorem :: PDIFF_5:73
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`31_in u0 & f2 is_hpartial_differentiable`31_in u0 holds
(pdiff1 f1,3) (#) (pdiff1 f2,3) is_partial_differentiable_in u0,1
proof end;

theorem :: PDIFF_5:74
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`32_in u0 & f2 is_hpartial_differentiable`32_in u0 holds
(pdiff1 f1,3) (#) (pdiff1 f2,3) is_partial_differentiable_in u0,2
proof end;

theorem :: PDIFF_5:75
for u0 being Element of REAL 3
for f1, f2 being PartFunc of (REAL 3),REAL st f1 is_hpartial_differentiable`33_in u0 & f2 is_hpartial_differentiable`33_in u0 holds
(pdiff1 f1,3) (#) (pdiff1 f2,3) is_partial_differentiable_in u0,3
proof end;

theorem :: PDIFF_5:76
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3 st f is_hpartial_differentiable`11_in u0 holds
SVF1 1,(pdiff1 f,1),u0 is_continuous_in (proj 1,3) . u0
proof end;

theorem :: PDIFF_5:77
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3 st f is_hpartial_differentiable`12_in u0 holds
SVF1 2,(pdiff1 f,1),u0 is_continuous_in (proj 2,3) . u0
proof end;

theorem :: PDIFF_5:78
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3 st f is_hpartial_differentiable`13_in u0 holds
SVF1 3,(pdiff1 f,1),u0 is_continuous_in (proj 3,3) . u0
proof end;

theorem :: PDIFF_5:79
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3 st f is_hpartial_differentiable`21_in u0 holds
SVF1 1,(pdiff1 f,2),u0 is_continuous_in (proj 1,3) . u0
proof end;

theorem :: PDIFF_5:80
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3 st f is_hpartial_differentiable`22_in u0 holds
SVF1 2,(pdiff1 f,2),u0 is_continuous_in (proj 2,3) . u0
proof end;

theorem :: PDIFF_5:81
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3 st f is_hpartial_differentiable`23_in u0 holds
SVF1 3,(pdiff1 f,2),u0 is_continuous_in (proj 3,3) . u0
proof end;

theorem :: PDIFF_5:82
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3 st f is_hpartial_differentiable`31_in u0 holds
SVF1 1,(pdiff1 f,3),u0 is_continuous_in (proj 1,3) . u0
proof end;

theorem :: PDIFF_5:83
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3 st f is_hpartial_differentiable`32_in u0 holds
SVF1 2,(pdiff1 f,3),u0 is_continuous_in (proj 2,3) . u0
proof end;

theorem :: PDIFF_5:84
for f being PartFunc of (REAL 3),REAL
for u0 being Element of REAL 3 st f is_hpartial_differentiable`33_in u0 holds
SVF1 3,(pdiff1 f,3),u0 is_continuous_in (proj 3,3) . u0
proof end;