:: by Library Committee

::

:: Received January 4, 2006

:: Copyright (c) 2006-2021 Association of Mizar Users

Lm0: not REAL in REAL

;

:: deftheorem Def1 defines ext-real XXREAL_0:def 1 :

for x being object holds

( x is ext-real iff x in ExtREAL );

for x being object holds

( x is ext-real iff x in ExtREAL );

registration

existence

ex b_{1} being object st b_{1} is ext-real

ex b_{1} being number st b_{1} is ext-real

for b_{1} being Element of ExtREAL holds b_{1} is ext-real
;

end;
ex b

proof end;

existence ex b

proof end;

coherence for b

registration
end;

definition
end;

definition

let x, y be ExtReal;

( x in REAL+ & y in REAL+ & x in [:{0},REAL+:] & y in [:{0},REAL+:] implies ( ex x9, y9 being Element of REAL+ st

( x = x9 & y = y9 & x9 <=' y9 ) iff ex x9, y9 being Element of REAL+ st

( x = [0,x9] & y = [0,y9] & y9 <=' x9 ) ) ) by ARYTM_0:5, XBOOLE_0:3;

reflexivity

for x being ExtReal holds

( ( x in REAL+ & x in REAL+ implies ex x9, y9 being Element of REAL+ st

( x = x9 & x = y9 & x9 <=' y9 ) ) & ( x in [:{0},REAL+:] & x in [:{0},REAL+:] implies ex x9, y9 being Element of REAL+ st

( x = [0,x9] & x = [0,y9] & y9 <=' x9 ) ) & ( ( not x in REAL+ or not x in REAL+ ) & ( not x in [:{0},REAL+:] or not x in [:{0},REAL+:] ) & not ( x in REAL+ & x in [:{0},REAL+:] ) & not x = -infty implies x = +infty ) )

for x, y being ExtReal st ( ( x in REAL+ & y in REAL+ & ( for x9, y9 being Element of REAL+ holds

( not x = x9 or not y = y9 or not x9 <=' y9 ) ) ) or ( x in [:{0},REAL+:] & y in [:{0},REAL+:] & ( for x9, y9 being Element of REAL+ holds

( not x = [0,x9] or not y = [0,y9] or not y9 <=' x9 ) ) ) or ( ( not x in REAL+ or not y in REAL+ ) & ( not x in [:{0},REAL+:] or not y in [:{0},REAL+:] ) & not ( y in REAL+ & x in [:{0},REAL+:] ) & not x = -infty & not y = +infty ) ) holds

( ( y in REAL+ & x in REAL+ implies ex x9, y9 being Element of REAL+ st

( y = x9 & x = y9 & x9 <=' y9 ) ) & ( y in [:{0},REAL+:] & x in [:{0},REAL+:] implies ex x9, y9 being Element of REAL+ st

( y = [0,x9] & x = [0,y9] & y9 <=' x9 ) ) & ( ( not y in REAL+ or not x in REAL+ ) & ( not y in [:{0},REAL+:] or not x in [:{0},REAL+:] ) & not ( x in REAL+ & y in [:{0},REAL+:] ) & not y = -infty implies x = +infty ) )

end;
pred x <= y means :Def5: :: XXREAL_0:def 5

ex x9, y9 being Element of REAL+ st

( x = x9 & y = y9 & x9 <=' y9 ) if ( x in REAL+ & y in REAL+ )

ex x9, y9 being Element of REAL+ st

( x = [0,x9] & y = [0,y9] & y9 <=' x9 ) if ( x in [:{0},REAL+:] & y in [:{0},REAL+:] )

otherwise ( ( y in REAL+ & x in [:{0},REAL+:] ) or x = -infty or y = +infty );

consistency ex x9, y9 being Element of REAL+ st

( x = x9 & y = y9 & x9 <=' y9 ) if ( x in REAL+ & y in REAL+ )

ex x9, y9 being Element of REAL+ st

( x = [0,x9] & y = [0,y9] & y9 <=' x9 ) if ( x in [:{0},REAL+:] & y in [:{0},REAL+:] )

otherwise ( ( y in REAL+ & x in [:{0},REAL+:] ) or x = -infty or y = +infty );

( x in REAL+ & y in REAL+ & x in [:{0},REAL+:] & y in [:{0},REAL+:] implies ( ex x9, y9 being Element of REAL+ st

( x = x9 & y = y9 & x9 <=' y9 ) iff ex x9, y9 being Element of REAL+ st

( x = [0,x9] & y = [0,y9] & y9 <=' x9 ) ) ) by ARYTM_0:5, XBOOLE_0:3;

reflexivity

for x being ExtReal holds

( ( x in REAL+ & x in REAL+ implies ex x9, y9 being Element of REAL+ st

( x = x9 & x = y9 & x9 <=' y9 ) ) & ( x in [:{0},REAL+:] & x in [:{0},REAL+:] implies ex x9, y9 being Element of REAL+ st

( x = [0,x9] & x = [0,y9] & y9 <=' x9 ) ) & ( ( not x in REAL+ or not x in REAL+ ) & ( not x in [:{0},REAL+:] or not x in [:{0},REAL+:] ) & not ( x in REAL+ & x in [:{0},REAL+:] ) & not x = -infty implies x = +infty ) )

proof end;

connectedness for x, y being ExtReal st ( ( x in REAL+ & y in REAL+ & ( for x9, y9 being Element of REAL+ holds

( not x = x9 or not y = y9 or not x9 <=' y9 ) ) ) or ( x in [:{0},REAL+:] & y in [:{0},REAL+:] & ( for x9, y9 being Element of REAL+ holds

( not x = [0,x9] or not y = [0,y9] or not y9 <=' x9 ) ) ) or ( ( not x in REAL+ or not y in REAL+ ) & ( not x in [:{0},REAL+:] or not y in [:{0},REAL+:] ) & not ( y in REAL+ & x in [:{0},REAL+:] ) & not x = -infty & not y = +infty ) ) holds

( ( y in REAL+ & x in REAL+ implies ex x9, y9 being Element of REAL+ st

( y = x9 & x = y9 & x9 <=' y9 ) ) & ( y in [:{0},REAL+:] & x in [:{0},REAL+:] implies ex x9, y9 being Element of REAL+ st

( y = [0,x9] & x = [0,y9] & y9 <=' x9 ) ) & ( ( not y in REAL+ or not x in REAL+ ) & ( not y in [:{0},REAL+:] or not x in [:{0},REAL+:] ) & not ( x in REAL+ & y in [:{0},REAL+:] ) & not y = -infty implies x = +infty ) )

proof end;

:: deftheorem Def5 defines <= XXREAL_0:def 5 :

for x, y being ExtReal holds

( ( x in REAL+ & y in REAL+ implies ( x <= y iff ex x9, y9 being Element of REAL+ st

( x = x9 & y = y9 & x9 <=' y9 ) ) ) & ( x in [:{0},REAL+:] & y in [:{0},REAL+:] implies ( x <= y iff ex x9, y9 being Element of REAL+ st

( x = [0,x9] & y = [0,y9] & y9 <=' x9 ) ) ) & ( ( not x in REAL+ or not y in REAL+ ) & ( not x in [:{0},REAL+:] or not y in [:{0},REAL+:] ) implies ( x <= y iff ( ( y in REAL+ & x in [:{0},REAL+:] ) or x = -infty or y = +infty ) ) ) );

for x, y being ExtReal holds

( ( x in REAL+ & y in REAL+ implies ( x <= y iff ex x9, y9 being Element of REAL+ st

( x = x9 & y = y9 & x9 <=' y9 ) ) ) & ( x in [:{0},REAL+:] & y in [:{0},REAL+:] implies ( x <= y iff ex x9, y9 being Element of REAL+ st

( x = [0,x9] & y = [0,y9] & y9 <=' x9 ) ) ) & ( ( not x in REAL+ or not y in REAL+ ) & ( not x in [:{0},REAL+:] or not y in [:{0},REAL+:] ) implies ( x <= y iff ( ( y in REAL+ & x in [:{0},REAL+:] ) or x = -infty or y = +infty ) ) ) );

notation
end;

Lm1: 0 in REAL

by NUMBERS:19;

Lm2: +infty <> [0,0]

proof end;

Lm3: not +infty in REAL+

by ARYTM_0:1, ORDINAL1:5;

Lm4: not -infty in REAL+

proof end;

Lm5: not +infty in [:{0},REAL+:]

proof end;

Lm6: not -infty in [:{0},REAL+:]

proof end;

Lm7: -infty < +infty

proof end;

Lm8: for a being ExtReal st -infty >= a holds

a = -infty

proof end;

Lm9: for a being ExtReal st +infty <= a holds

a = +infty

proof end;

Lm10: for a being ExtReal holds

( a in REAL or a = +infty or a = -infty )

proof end;

registration

coherence

for b_{1} being object st b_{1} is natural holds

b_{1} is ext-real
by NUMBERS:19, XBOOLE_0:def 3;

end;
for b

b

:: deftheorem defines positive XXREAL_0:def 6 :

for a being ExtReal holds

( a is positive iff a > 0 );

for a being ExtReal holds

( a is positive iff a > 0 );

:: deftheorem defines negative XXREAL_0:def 7 :

for a being ExtReal holds

( a is negative iff a < 0 );

for a being ExtReal holds

( a is negative iff a < 0 );

registration

coherence

for b_{1} being ExtReal st b_{1} is positive holds

( not b_{1} is negative & not b_{1} is zero )
;

coherence

for b_{1} being ExtReal st not b_{1} is negative & not b_{1} is zero holds

b_{1} is positive
by Th1;

coherence

for b_{1} being ExtReal st b_{1} is negative holds

( not b_{1} is positive & not b_{1} is zero )
;

coherence

for b_{1} being ExtReal st not b_{1} is positive & not b_{1} is zero holds

b_{1} is negative
;

coherence

for b_{1} being ExtReal st b_{1} is zero holds

( not b_{1} is negative & not b_{1} is positive )
;

coherence

for b_{1} being ExtReal st not b_{1} is negative & not b_{1} is positive holds

b_{1} is zero
;

end;
for b

( not b

coherence

for b

b

coherence

for b

( not b

coherence

for b

b

coherence

for b

( not b

coherence

for b

b

registration
end;

registration

existence

ex b_{1} being ExtReal st b_{1} is positive

ex b_{1} being ExtReal st b_{1} is negative

ex b_{1} being ExtReal st b_{1} is zero

end;
ex b

proof end;

existence ex b

proof end;

existence ex b

proof end;

definition

let a, b be ExtReal;

correctness

coherence

( ( a <= b implies a is ExtReal ) & ( not a <= b implies b is ExtReal ) );

consistency

for b_{1} being ExtReal holds verum;

;

commutativity

for b_{1}, a, b being ExtReal st ( a <= b implies b_{1} = a ) & ( not a <= b implies b_{1} = b ) holds

( ( b <= a implies b_{1} = b ) & ( not b <= a implies b_{1} = a ) )
by Th1;

idempotence

for a being ExtReal holds

( ( a <= a implies a = a ) & ( not a <= a implies a = a ) ) ;

correctness

coherence

( ( b <= a implies a is ExtReal ) & ( not b <= a implies b is ExtReal ) );

consistency

for b_{1} being ExtReal holds verum;

;

commutativity

for b_{1}, a, b being ExtReal st ( b <= a implies b_{1} = a ) & ( not b <= a implies b_{1} = b ) holds

( ( a <= b implies b_{1} = b ) & ( not a <= b implies b_{1} = a ) )
by Th1;

idempotence

for a being ExtReal holds

( ( a <= a implies a = a ) & ( not a <= a implies a = a ) ) ;

end;
correctness

coherence

( ( a <= b implies a is ExtReal ) & ( not a <= b implies b is ExtReal ) );

consistency

for b

;

commutativity

for b

( ( b <= a implies b

idempotence

for a being ExtReal holds

( ( a <= a implies a = a ) & ( not a <= a implies a = a ) ) ;

correctness

coherence

( ( b <= a implies a is ExtReal ) & ( not b <= a implies b is ExtReal ) );

consistency

for b

;

commutativity

for b

( ( a <= b implies b

idempotence

for a being ExtReal holds

( ( a <= a implies a = a ) & ( not a <= a implies a = a ) ) ;

:: deftheorem Def8 defines min XXREAL_0:def 9 :

for a, b being ExtReal holds

( ( a <= b implies min (a,b) = a ) & ( not a <= b implies min (a,b) = b ) );

for a, b being ExtReal holds

( ( a <= b implies min (a,b) = a ) & ( not a <= b implies min (a,b) = b ) );

:: deftheorem Def9 defines max XXREAL_0:def 10 :

for a, b being ExtReal holds

( ( b <= a implies max (a,b) = a ) & ( not b <= a implies max (a,b) = b ) );

for a, b being ExtReal holds

( ( b <= a implies max (a,b) = a ) & ( not b <= a implies max (a,b) = b ) );

registration
end;

theorem :: XXREAL_0:24

for a, b, c being ExtReal st c <= a & c <= b & ( for d being ExtReal st d <= a & d <= b holds

d <= c ) holds

c = min (a,b)

d <= c ) holds

c = min (a,b)

proof end;

theorem :: XXREAL_0:32

for a, b, c being ExtReal st a <= c & b <= c & ( for d being ExtReal st a <= d & b <= d holds

c <= d ) holds

c = max (a,b)

c <= d ) holds

c = max (a,b)

proof end;

theorem :: XXREAL_0:40

for a, b, c being ExtReal holds max ((max ((min (a,b)),(min (b,c)))),(min (c,a))) = min ((min ((max (a,b)),(max (b,c)))),(max (c,a)))

proof end;

:: from AMI_2, 2008.02.14, A.T.

definition

let x, y be ExtReal;

let a, b be object ;

correctness

coherence

( ( x > y implies a is object ) & ( not x > y implies b is object ) );

consistency

for b_{1} being object holds verum;

;

end;
let a, b be object ;

correctness

coherence

( ( x > y implies a is object ) & ( not x > y implies b is object ) );

consistency

for b

;

:: deftheorem Def10 defines IFGT XXREAL_0:def 11 :

for x, y being ExtReal

for a, b being object holds

( ( x > y implies IFGT (x,y,a,b) = a ) & ( not x > y implies IFGT (x,y,a,b) = b ) );

for x, y being ExtReal

for a, b being object holds

( ( x > y implies IFGT (x,y,a,b) = a ) & ( not x > y implies IFGT (x,y,a,b) = b ) );

registration
end;

:: from TOPREAL7, 2008.07.05, A.T.

:: let a be number;

:: synonym a is zero for a is empty;

:: end;