let a, b, p, q be Real; ( 1 < p & (1 / p) + (1 / q) = 1 & 0 < a & 0 < b implies ( a * b <= ((a #R p) / p) + ((b #R q) / q) & ( a * b = ((a #R p) / p) + ((b #R q) / q) implies a #R p = b #R q ) & ( a #R p = b #R q implies a * b = ((a #R p) / p) + ((b #R q) / q) ) ) )
assume that
A1:
1 < p
and
A2:
(1 / p) + (1 / q) = 1
and
A3:
0 < a
and
A4:
0 < b
; ( a * b <= ((a #R p) / p) + ((b #R q) / q) & ( a * b = ((a #R p) / p) + ((b #R q) / q) implies a #R p = b #R q ) & ( a #R p = b #R q implies a * b = ((a #R p) / p) + ((b #R q) / q) ) )
A5:
0 < b #R q
by A4, PREPOWER:81;
reconsider pp = 1 / p as Real ;
1 - pp <> 0
by A1, XREAL_1:189;
then A6:
(q ") " <> 0
by A2;
then
(((1 * q) + (1 * p)) / (p * q)) * (p * q) = 1 * (p * q)
by A1, A2, XCMPLX_1:116;
then A7:
q + p = p * q
by A1, A6, XCMPLX_1:6, XCMPLX_1:87;
then A8:
(q - 1) * p = q
;
A9:
0 < b #R (q - 1)
by A4, PREPOWER:81;
A10:
now ( a #R p = b #R q implies ((a #R p) / p) + ((b #R q) / q) = a * b )assume A11:
a #R p = b #R q
;
((a #R p) / p) + ((b #R q) / q) = a * bthen A12:
a #R p = (b #R (q - 1)) #R p
by A4, A8, PREPOWER:91;
a =
a #R 1
by A3, PREPOWER:72
.=
a #R (p * (1 / p))
by A1, XCMPLX_1:106
.=
(a #R p) #R (1 / p)
by A3, PREPOWER:91
.=
(b #R (q - 1)) #R (p * (1 / p))
by A4, A12, PREPOWER:81, PREPOWER:91
.=
(b #R (q - 1)) #R 1
by A1, XCMPLX_1:106
.=
b #R (q - 1)
by A4, PREPOWER:72, PREPOWER:81
;
then
a * 1
= b #R (q - 1)
;
then
a * (b #R ((1 - q) + (q - 1))) = b #R (q - 1)
by A4, PREPOWER:71;
then
a * ((b #R (1 - q)) * (b #R (q - 1))) = 1
* (b #R (q - 1))
by A4, PREPOWER:75;
then A13:
(a * (b #R (1 - q))) * (b #R (q - 1)) = 1
* (b #R (q - 1))
;
thus ((a #R p) / p) + ((b #R q) / q) =
((b #R q) * (1 / p)) + ((b #R q) / q)
by A11, XCMPLX_1:99
.=
((b #R q) * (1 / p)) + ((b #R q) * (1 / q))
by XCMPLX_1:99
.=
(b #R q) * ((1 / p) + (1 / q))
.=
(b #R q) * (a * (b #R (1 - q)))
by A2, A9, A13, XCMPLX_1:5
.=
a * ((b #R (1 - q)) * (b #R q))
.=
a * (b #R ((1 - q) + q))
by A4, PREPOWER:75
.=
a * b
by A4, PREPOWER:72
;
verum end;
A14:
0 < b #R (1 - q)
by A4, PREPOWER:81;
then A15:
0 * (b #R (1 - q)) < a * (b #R (1 - q))
by A3, XREAL_1:68;
ex h being PartFunc of REAL,REAL st
( dom h = right_open_halfline 0 & ( for x being Real st x > 0 holds
( h . x = (x #R p) / p & h is_differentiable_in x & diff (h,x) = x #R (p - 1) ) ) )
proof
set h =
(1 / p) (#) (#R p);
take
(1 / p) (#) (#R p)
;
( dom ((1 / p) (#) (#R p)) = right_open_halfline 0 & ( for x being Real st x > 0 holds
( ((1 / p) (#) (#R p)) . x = (x #R p) / p & (1 / p) (#) (#R p) is_differentiable_in x & diff (((1 / p) (#) (#R p)),x) = x #R (p - 1) ) ) )
dom (#R p) = right_open_halfline 0
by TAYLOR_1:def 4;
hence A16:
dom ((1 / p) (#) (#R p)) = right_open_halfline 0
by VALUED_1:def 5;
for x being Real st x > 0 holds
( ((1 / p) (#) (#R p)) . x = (x #R p) / p & (1 / p) (#) (#R p) is_differentiable_in x & diff (((1 / p) (#) (#R p)),x) = x #R (p - 1) )
now for x being Real st x > 0 holds
( ((1 / p) (#) (#R p)) . x = (x #R p) / p & (1 / p) (#) (#R p) is_differentiable_in x & diff (((1 / p) (#) (#R p)),x) = x #R (p - 1) )let x be
Real;
( x > 0 implies ( ((1 / p) (#) (#R p)) . x = (x #R p) / p & (1 / p) (#) (#R p) is_differentiable_in x & diff (((1 / p) (#) (#R p)),x) = x #R (p - 1) ) )assume A17:
x > 0
;
( ((1 / p) (#) (#R p)) . x = (x #R p) / p & (1 / p) (#) (#R p) is_differentiable_in x & diff (((1 / p) (#) (#R p)),x) = x #R (p - 1) )
x in { g where g is Real : 0 < g }
by A17;
then A18:
x in right_open_halfline 0
by XXREAL_1:230;
hence ((1 / p) (#) (#R p)) . x =
(1 / p) * ((#R p) . x)
by A16, VALUED_1:def 5
.=
(1 / p) * (x #R p)
by A18, TAYLOR_1:def 4
.=
(x #R p) / p
by XCMPLX_1:99
;
( (1 / p) (#) (#R p) is_differentiable_in x & diff (((1 / p) (#) (#R p)),x) = x #R (p - 1) )A19:
#R p is_differentiable_in x
by A17, TAYLOR_1:21;
hence
(1 / p) (#) (#R p) is_differentiable_in x
by FDIFF_1:15;
diff (((1 / p) (#) (#R p)),x) = x #R (p - 1)thus diff (
((1 / p) (#) (#R p)),
x) =
(1 / p) * (diff ((#R p),x))
by A19, FDIFF_1:15
.=
(1 / p) * (p * (x #R (p - 1)))
by A17, TAYLOR_1:21
.=
((1 / p) * p) * (x #R (p - 1))
.=
1
* (x #R (p - 1))
by A1, XCMPLX_1:106
.=
x #R (p - 1)
;
verum end;
hence
for
x being
Real st
x > 0 holds
(
((1 / p) (#) (#R p)) . x = (x #R p) / p &
(1 / p) (#) (#R p) is_differentiable_in x &
diff (
((1 / p) (#) (#R p)),
x)
= x #R (p - 1) )
;
verum
end;
then consider h being PartFunc of REAL,REAL such that
A20:
dom h = right_open_halfline 0
and
A21:
for x being Real st x > 0 holds
( h . x = (x #R p) / p & h is_differentiable_in x & diff (h,x) = x #R (p - 1) )
;
ex g being PartFunc of REAL,REAL st
( dom g = REAL & ( for x being Element of REAL holds
( g . x = (1 / q) - x & g is_differentiable_in x & diff (g,x) = - 1 ) ) )
then consider g being PartFunc of REAL,REAL such that
A30:
dom g = REAL
and
A31:
for x being Element of REAL holds g . x = (1 / q) - x
and
A32:
for x being Element of REAL holds
( g is_differentiable_in x & diff (g,x) = - 1 )
;
set f = h + g;
A33: dom (h + g) =
(right_open_halfline 0) /\ REAL
by A30, A20, VALUED_1:def 1
.=
right_open_halfline 0
by XBOOLE_1:28
;
A34:
for x being Real st x in right_open_halfline 0 holds
( (h + g) . x = (((x #R p) / p) + (1 / q)) - x & h + g is_differentiable_in x & diff ((h + g),x) = (x #R (p - 1)) - 1 )
proof
let x be
Real;
( x in right_open_halfline 0 implies ( (h + g) . x = (((x #R p) / p) + (1 / q)) - x & h + g is_differentiable_in x & diff ((h + g),x) = (x #R (p - 1)) - 1 ) )
assume A35:
x in right_open_halfline 0
;
( (h + g) . x = (((x #R p) / p) + (1 / q)) - x & h + g is_differentiable_in x & diff ((h + g),x) = (x #R (p - 1)) - 1 )
reconsider xx =
x as
Element of
REAL by XREAL_0:def 1;
x in { y where y is Real : 0 < y }
by A35, XXREAL_1:230;
then A36:
ex
y being
Real st
(
x = y &
0 < y )
;
then A37:
diff (
h,
x)
= x #R (p - 1)
by A21;
thus (h + g) . x =
(h . x) + (g . x)
by A33, A35, VALUED_1:def 1
.=
((x #R p) / p) + (g . xx)
by A21, A36
.=
((x #R p) / p) + ((1 / q) - x)
by A31
.=
(((x #R p) / p) + (1 / q)) - x
;
( h + g is_differentiable_in x & diff ((h + g),x) = (x #R (p - 1)) - 1 )
A38:
g is_differentiable_in xx
by A32;
A39:
h is_differentiable_in x
by A21, A36;
hence
h + g is_differentiable_in x
by A38, FDIFF_1:13;
diff ((h + g),x) = (x #R (p - 1)) - 1
A40:
diff (
g,
xx)
= - 1
by A32;
thus diff (
(h + g),
x) =
(diff (h,x)) + (diff (g,x))
by A38, A39, FDIFF_1:13
.=
(x #R (p - 1)) - 1
by A40, A37
;
verum
end;
A41:
for x being Real st 0 < x & x <> 1 holds
x < ((x #R p) / p) + (1 / q)
proof
1
in { y where y is Real : 0 < y }
;
then
1
in right_open_halfline 0
by XXREAL_1:230;
then A42:
(h + g) . 1 =
(((1 #R p) / p) + (1 / q)) - 1
by A34
.=
((1 / p) + (1 / q)) - 1
by PREPOWER:73
.=
0
by A2
;
for
x being
Real st
x in right_open_halfline 0 holds
h + g is_differentiable_in x
by A34;
then A43:
h + g is_differentiable_on right_open_halfline 0
by A33, FDIFF_1:9;
let x be
Real;
( 0 < x & x <> 1 implies x < ((x #R p) / p) + (1 / q) )
assume that A44:
0 < x
and A45:
x <> 1
;
x < ((x #R p) / p) + (1 / q)
x in { y where y is Real : 0 < y }
by A44;
then A46:
x in right_open_halfline 0
by XXREAL_1:230;
now ( ( x < 1 & x < ((x #R p) / p) + (1 / q) ) or ( x > 1 & x < ((x #R p) / p) + (1 / q) ) )per cases
( x < 1 or x > 1 )
by A45, XXREAL_0:1;
case
x < 1
;
x < ((x #R p) / p) + (1 / q)then A47:
1
- 1
< 1
- x
by XREAL_1:15;
set t = 1
- x;
A48:
1
- 1
< p - 1
by A1, XREAL_1:14;
then A49:
[.x,(x + (1 - x)).] c= right_open_halfline 0
;
(h + g) | (right_open_halfline 0) is
continuous
by A43, FDIFF_1:25;
then A50:
(h + g) | [.x,(x + (1 - x)).] is
continuous
by A49, FCONT_1:16;
].x,(x + (1 - x)).[ c= [.x,(x + (1 - x)).]
by XXREAL_1:25;
then
h + g is_differentiable_on ].x,(x + (1 - x)).[
by A43, A49, FDIFF_1:26, XBOOLE_1:1;
then consider s being
Real such that A51:
0 < s
and A52:
s < 1
and A53:
(h + g) . (x + (1 - x)) = ((h + g) . x) + ((1 - x) * (diff ((h + g),(x + (s * (1 - x))))))
by A33, A47, A49, A50, ROLLE:4;
s * (1 - x) < 1
* (1 - x)
by A47, A52, XREAL_1:68;
then
x + (s * (1 - x)) < x + (1 - x)
by XREAL_1:8;
then
(x + (s * (1 - x))) to_power (p - 1) < (x + (s * (1 - x))) to_power 0
by A44, A47, A51, A48, POWER:40;
then
(x + (s * (1 - x))) #R (p - 1) < (x + (s * (1 - x))) to_power 0
by A44, A47, A51, POWER:def 2;
then
(x + (s * (1 - x))) #R (p - 1) < (x + (s * (1 - x))) #R 0
by A44, A47, A51, POWER:def 2;
then
(x + (s * (1 - x))) #R (p - 1) < 1
by A44, A47, A51, PREPOWER:71;
then A54:
((x + (s * (1 - x))) #R (p - 1)) - 1
< 1
- 1
by XREAL_1:14;
x + (s * (1 - x)) in { y where y is Real : 0 < y }
by A44, A47, A51;
then
x + (s * (1 - x)) in right_open_halfline 0
by XXREAL_1:230;
then
diff (
(h + g),
(x + (s * (1 - x))))
= ((x + (s * (1 - x))) #R (p - 1)) - 1
by A34;
then
(1 - x) * (diff ((h + g),(x + (s * (1 - x))))) < (1 - x) * 0
by A47, A54, XREAL_1:68;
then
((h + g) . x) + ((1 - x) * (diff ((h + g),(x + (s * (1 - x)))))) < ((h + g) . x) + 0
by XREAL_1:8;
then
0 < (((x #R p) / p) + (1 / q)) - x
by A34, A46, A42, A53;
then
0 + x < ((((x #R p) / p) + (1 / q)) - x) + x
by XREAL_1:8;
hence
x < ((x #R p) / p) + (1 / q)
;
verum end; case
x > 1
;
x < ((x #R p) / p) + (1 / q)then A55:
1
- 1
< x - 1
by XREAL_1:14;
set t =
x - 1;
then A56:
[.1,(1 + (x - 1)).] c= right_open_halfline 0
;
A57:
1
- 1
< p - 1
by A1, XREAL_1:14;
(h + g) | (right_open_halfline 0) is
continuous
by A43, FDIFF_1:25;
then A58:
(h + g) | [.1,(1 + (x - 1)).] is
continuous
by A56, FCONT_1:16;
].1,(1 + (x - 1)).[ c= [.1,(1 + (x - 1)).]
by XXREAL_1:25;
then
h + g is_differentiable_on ].1,(1 + (x - 1)).[
by A43, A56, FDIFF_1:26, XBOOLE_1:1;
then consider s being
Real such that A59:
0 < s
and
s < 1
and A60:
(h + g) . (1 + (x - 1)) = ((h + g) . 1) + ((x - 1) * (diff ((h + g),(1 + (s * (x - 1))))))
by A33, A55, A56, A58, ROLLE:4;
0 * (x - 1) < s * (x - 1)
by A55, A59, XREAL_1:68;
then
1
+ 0 < 1
+ (s * (x - 1))
by XREAL_1:8;
then
1
< (1 + (s * (x - 1))) #R (p - 1)
by A57, PREPOWER:86;
then A61:
1
- 1
< ((1 + (s * (x - 1))) #R (p - 1)) - 1
by XREAL_1:14;
1
+ (s * (x - 1)) in { y where y is Real : 0 < y }
by A55, A59;
then
1
+ (s * (x - 1)) in right_open_halfline 0
by XXREAL_1:230;
then
diff (
(h + g),
(1 + (s * (x - 1))))
= ((1 + (s * (x - 1))) #R (p - 1)) - 1
by A34;
then
(x - 1) * 0 < (x - 1) * (diff ((h + g),(1 + (s * (x - 1)))))
by A55, A61, XREAL_1:68;
then
0 < (((x #R p) / p) + (1 / q)) - x
by A34, A46, A42, A60;
then
0 + x < ((((x #R p) / p) + (1 / q)) - x) + x
by XREAL_1:8;
hence
x < ((x #R p) / p) + (1 / q)
;
verum end; end; end;
hence
x < ((x #R p) / p) + (1 / q)
;
verum
end;
A62:
((1 - q) * p) + q = 0
by A7;
A63:
now ( a * b = ((a #R p) / p) + ((b #R q) / q) implies a #R p = b #R q )assume
a * b = ((a #R p) / p) + ((b #R q) / q)
;
a #R p = b #R qthen
a * b = ((a #R p) / p) + ((1 / q) * (b #R q))
by XCMPLX_1:99;
then
a * b = ((a #R p) * (1 / p)) + ((1 / q) * (b #R q))
by XCMPLX_1:99;
then
a * b = ((a #R p) * ((b #R 0) / p)) + ((1 / q) * (b #R q))
by A4, PREPOWER:71;
then
a * b = ((a #R p) * (((b #R ((1 - q) * p)) * (b #R q)) / p)) + ((1 / q) * (b #R q))
by A4, A62, PREPOWER:75;
then
a * b = ((a #R p) * (((b #R ((1 - q) * p)) / p) * (b #R q))) + ((1 / q) * (b #R q))
by XCMPLX_1:74;
then
a * b = (((a #R p) * ((b #R ((1 - q) * p)) / p)) * (b #R q)) + ((1 / q) * (b #R q))
;
then
a * b = ((((a #R p) * (b #R ((1 - q) * p))) / p) * (b #R q)) + ((1 / q) * (b #R q))
by XCMPLX_1:74;
then
a * b = ((((a #R p) * (b #R ((1 - q) * p))) / p) + (1 / q)) * (b #R q)
;
then
a * b = ((((a #R p) * ((b #R (1 - q)) #R p)) / p) + (1 / q)) * (b #R q)
by A4, PREPOWER:91;
then
a * b = ((((a * (b #R (1 - q))) #R p) / p) + (1 / q)) * (b #R q)
by A3, A14, PREPOWER:78;
then
a * (b #R ((1 - q) + q)) = ((((a * (b #R (1 - q))) #R p) / p) + (1 / q)) * (b #R q)
by A4, PREPOWER:72;
then
a * ((b #R (1 - q)) * (b #R q)) = ((((a * (b #R (1 - q))) #R p) / p) + (1 / q)) * (b #R q)
by A4, PREPOWER:75;
then
(a * (b #R (1 - q))) * (b #R q) = ((((a * (b #R (1 - q))) #R p) / p) + (1 / q)) * (b #R q)
;
then A64:
a * (b #R (1 - q)) = (((a * (b #R (1 - q))) #R p) / p) + (1 / q)
by A5, XCMPLX_1:5;
a * ((b #R (1 - q)) * (b #R (q - 1))) =
(a * (b #R (1 - q))) * (b #R (q - 1))
.=
1
* (b #R (q - 1))
by A41, A15, A64
;
then
a * (b #R ((1 - q) + (q - 1))) = b #R (q - 1)
by A4, PREPOWER:75;
then
a * 1
= b #R (q - 1)
by A4, PREPOWER:71;
hence
a #R p = b #R q
by A4, A8, PREPOWER:91;
verum end;
a * (b #R (1 - q)) <= (((a * (b #R (1 - q))) #R p) / p) + (1 / q)
then
(a * (b #R (1 - q))) * (b #R q) <= ((((a * (b #R (1 - q))) #R p) / p) + (1 / q)) * (b #R q)
by A5, XREAL_1:64;
then
a * ((b #R (1 - q)) * (b #R q)) <= ((((a * (b #R (1 - q))) #R p) / p) + (1 / q)) * (b #R q)
;
then
a * (b #R ((1 - q) + q)) <= ((((a * (b #R (1 - q))) #R p) / p) + (1 / q)) * (b #R q)
by A4, PREPOWER:75;
then
a * b <= ((((a * (b #R (1 - q))) #R p) / p) + (1 / q)) * (b #R q)
by A4, PREPOWER:72;
then
a * b <= ((((a #R p) * ((b #R (1 - q)) #R p)) / p) + (1 / q)) * (b #R q)
by A3, A14, PREPOWER:78;
then
a * b <= ((((a #R p) * (b #R ((1 - q) * p))) / p) + (1 / q)) * (b #R q)
by A4, PREPOWER:91;
then
a * b <= ((((a #R p) * (b #R ((1 - q) * p))) / p) * (b #R q)) + ((1 / q) * (b #R q))
;
then
a * b <= (((a #R p) * ((b #R ((1 - q) * p)) / p)) * (b #R q)) + ((1 / q) * (b #R q))
by XCMPLX_1:74;
then
a * b <= ((a #R p) * (((b #R ((1 - q) * p)) / p) * (b #R q))) + ((1 / q) * (b #R q))
;
then
a * b <= ((a #R p) * (((b #R ((1 - q) * p)) * (b #R q)) / p)) + ((1 / q) * (b #R q))
by XCMPLX_1:74;
then
a * b <= ((a #R p) * ((b #R (((1 - q) * p) + q)) / p)) + ((1 / q) * (b #R q))
by A4, PREPOWER:75;
then
a * b <= ((a #R p) * (1 / p)) + ((1 / q) * (b #R q))
by A4, A7, PREPOWER:71;
then
a * b <= ((a #R p) / p) + ((1 / q) * (b #R q))
by XCMPLX_1:99;
hence
( a * b <= ((a #R p) / p) + ((b #R q) / q) & ( a * b = ((a #R p) / p) + ((b #R q) / q) implies a #R p = b #R q ) & ( a #R p = b #R q implies a * b = ((a #R p) / p) + ((b #R q) / q) ) )
by A63, A10, XCMPLX_1:99; verum