:: Curried and Uncurried Functions
:: by Grzegorz Bancerek
::
:: Received March 6, 1990
:: Copyright (c) 1990-2021 Association of Mizar Users

scheme :: FUNCT_5:sch 1
LambdaFS{ F₁() -> set , F₂( object ) -> object } :

ex f being Function st
( dom f = F₁() & ( for g being Function st g in F₁() holds
f . g = F₂(g) ) )

proof end;

theorem Th1: :: FUNCT_5:1

~ {} = {}

proof end;

theorem :: FUNCT_5:2

canceled;

theorem :: FUNCT_5:3

canceled;

theorem :: FUNCT_5:4

canceled;

theorem :: FUNCT_5:5

canceled;

theorem :: FUNCT_5:6

canceled;

theorem :: FUNCT_5:7

canceled;

::$CT 6

theorem Th2: :: FUNCT_5:8

( proj1 {} = {} & proj2 {} = {} ) ;

theorem Th3: :: FUNCT_5:9

for X, Y being set st ( Y <> {} or [:X,Y:] <> {} or [:Y,X:] <> {} ) holds
( proj1 [:X,Y:] = X & proj2 [:Y,X:] = X )

proof end;

theorem Th4: :: FUNCT_5:10

for X, Y being set holds
( proj1 [:X,Y:] c= X & proj2 [:X,Y:] c= Y )

proof end;

theorem Th5: :: FUNCT_5:11

for X, Y, Z being set st Z c= [:X,Y:] holds
( proj1 Z c= X & proj2 Z c= Y )

proof end;

theorem Th6: :: FUNCT_5:12

for x, y being object holds
( proj1 {[x,y]} = {x} & proj2 {[x,y]} = {y} )

proof end;

theorem :: FUNCT_5:13

for x, y, z, t being object holds
( proj1 {[x,y],[z,t]} = {x,z} & proj2 {[x,y],[z,t]} = {y,t} )

proof end;

theorem Th8: :: FUNCT_5:14

for X being set st ( for x, y being object holds not [x,y] in X ) holds
( proj1 X = {} & proj2 X = {} )

proof end;

theorem :: FUNCT_5:15

for X being set st ( proj1 X = {} or proj2 X = {} ) holds
for x, y being object holds not [x,y] in X by XTUPLE_0:def 12, XTUPLE_0:def 13;

theorem :: FUNCT_5:16

for X being set holds
( proj1 X = {} iff proj2 X = {} )

proof end;

theorem Th11: :: FUNCT_5:17

for f being Function holds
( proj1 (dom f) = proj2 (dom (~ f)) & proj2 (dom f) = proj1 (dom (~ f)) )

proof end;

definition

let f be Function;

func curry f -> Function means :Def1: :: FUNCT_5:def 1
( dom it = proj1 (dom f) & ( for x being object st x in proj1 (dom f) holds
ex g being Function st
( it . x = g & dom g = proj2 ((dom f) /\ [:{x},(proj2 (dom f)):]) & ( for y being object st y in dom g holds
g . y = f . (x,y) ) ) ) );

existence
ex b₁ being Function st
( dom b₁ = proj1 (dom f) & ( for x being object st x in proj1 (dom f) holds
ex g being Function st
( b₁ . x = g & dom g = proj2 ((dom f) /\ [:{x},(proj2 (dom f)):]) & ( for y being object st y in dom g holds
g . y = f . (x,y) ) ) ) )

proof end;

uniqueness
for b₁, b₂ being Function st dom b₁ = proj1 (dom f) & ( for x being object st x in proj1 (dom f) holds
ex g being Function st
( b₁ . x = g & dom g = proj2 ((dom f) /\ [:{x},(proj2 (dom f)):]) & ( for y being object st y in dom g holds
g . y = f . (x,y) ) ) ) & dom b₂ = proj1 (dom f) & ( for x being object st x in proj1 (dom f) holds
ex g being Function st
( b₂ . x = g & dom g = proj2 ((dom f) /\ [:{x},(proj2 (dom f)):]) & ( for y being object st y in dom g holds
g . y = f . (x,y) ) ) ) holds
b₁ = b₂

proof end;

func uncurry f -> Function means :Def2: :: FUNCT_5:def 2
( ( for t being object holds
( t in dom it iff ex x being object ex g being Function ex y being object st
( t = [x,y] & x in dom f & g = f . x & y in dom g ) ) ) & ( for x being object
for g being Function st x in dom it & g = f . (x `1) holds
it . x = g . (x `2) ) );

existence
ex b₁ being Function st
( ( for t being object holds
( t in dom b₁ iff ex x being object ex g being Function ex y being object st
( t = [x,y] & x in dom f & g = f . x & y in dom g ) ) ) & ( for x being object
for g being Function st x in dom b₁ & g = f . (x `1) holds
b<sub>1</sub> . x = g . (x `2) ) )

proof end;

uniqueness
for b₁, b₂ being Function st ( for t being object holds
( t in dom b₁ iff ex x being object ex g being Function ex y being object st
( t = [x,y] & x in dom f & g = f . x & y in dom g ) ) ) & ( for x being object
for g being Function st x in dom b₁ & g = f . (x `1) holds
b<sub>1</sub> . x = g . (x `2) ) & ( for t being object holds
( t in dom b₂ iff ex x being object ex g being Function ex y being object st
( t = [x,y] & x in dom f & g = f . x & y in dom g ) ) ) & ( for x being object
for g being Function st x in dom b₂ & g = f . (x `1) holds
b<sub>2</sub> . x = g . (x `2) ) holds
b₁ = b₂

proof end;

end;

:: deftheorem Def1 defines curry FUNCT_5:def 1 :
for f, b₂ being Function holds
( b₂ = curry f iff ( dom b₂ = proj1 (dom f) & ( for x being object st x in proj1 (dom f) holds
ex g being Function st
( b₂ . x = g & dom g = proj2 ((dom f) /\ [:{x},(proj2 (dom f)):]) & ( for y being object st y in dom g holds
g . y = f . (x,y) ) ) ) ) );

:: deftheorem Def2 defines uncurry FUNCT_5:def 2 :
for f, b₂ being Function holds
( b₂ = uncurry f iff ( ( for t being object holds
( t in dom b₂ iff ex x being object ex g being Function ex y being object st
( t = [x,y] & x in dom f & g = f . x & y in dom g ) ) ) & ( for x being object
for g being Function st x in dom b₂ & g = f . (x `1) holds
b<sub>2</sub> . x = g . (x `2) ) ) );

definition

let f be Function;

func curry' f -> Function equals :: FUNCT_5:def 3
curry (~ f);

correctness
coherence
curry (~ f) is Function;
;

func uncurry' f -> Function equals :: FUNCT_5:def 4
~ (uncurry f);

correctness
coherence
~ (uncurry f) is Function;
;

end;

:: deftheorem defines curry' FUNCT_5:def 3 :
for f being Function holds curry' f = curry (~ f);

:: deftheorem defines uncurry' FUNCT_5:def 4 :
for f being Function holds uncurry' f = ~ (uncurry f);

theorem :: FUNCT_5:18

canceled;

::$CT

registration

let f be Function;

cluster curry f -> Function-yielding ;

coherence
curry f is Function-yielding

proof end;

end;

theorem Th12: :: FUNCT_5:19

for f being Function
for x, y being object st [x,y] in dom f holds
x in dom (curry f)

proof end;

theorem Th13: :: FUNCT_5:20

for f, g being Function
for x, y being object st [x,y] in dom f & g = (curry f) . x holds
( y in dom g & g . y = f . (x,y) )

proof end;

registration

let f be Function;

cluster curry' f -> Function-yielding ;

coherence
curry' f is Function-yielding ;

end;

theorem :: FUNCT_5:21

for f being Function
for x, y being object st [x,y] in dom f holds
y in dom (curry' f)

proof end;

theorem Th15: :: FUNCT_5:22

for f, g being Function
for x, y being object st [x,y] in dom f & g = (curry' f) . y holds
( x in dom g & g . x = f . (x,y) )

proof end;

theorem :: FUNCT_5:23

for f being Function holds dom (curry' f) = proj2 (dom f)

proof end;

theorem Th17: :: FUNCT_5:24

for X, Y being set
for f being Function st [:X,Y:] <> {} & dom f = [:X,Y:] holds
( dom (curry f) = X & dom (curry' f) = Y )

proof end;

theorem Th18: :: FUNCT_5:25

for X, Y being set
for f being Function st dom f c= [:X,Y:] holds
( dom (curry f) c= X & dom (curry' f) c= Y )

proof end;

theorem Th19: :: FUNCT_5:26

for X, Y being set
for f being Function st rng f c= Funcs (X,Y) holds
( dom (uncurry f) = [:(dom f),X:] & dom (uncurry' f) = [:X,(dom f):] )

proof end;

theorem :: FUNCT_5:27

for f being Function st ( for x, y being object holds not [x,y] in dom f ) holds
( curry f = {} & curry' f = {} )

proof end;

theorem :: FUNCT_5:28

for f being Function st ( for x being object holds
( not x in dom f or not f . x is Function ) ) holds
( uncurry f = {} & uncurry' f = {} )

proof end;

theorem Th22: :: FUNCT_5:29

for X, Y being set
for x being object
for f being Function st [:X,Y:] <> {} & dom f = [:X,Y:] & x in X holds
ex g being Function st
( (curry f) . x = g & dom g = Y & rng g c= rng f & ( for y being object st y in Y holds
g . y = f . (x,y) ) )

proof end;

theorem Th23: :: FUNCT_5:30

for x being object
for f being Function st x in dom (curry f) holds
(curry f) . x is Function

proof end;

theorem Th24: :: FUNCT_5:31

for x being object
for f, g being Function st x in dom (curry f) & g = (curry f) . x holds
( dom g = proj2 ((dom f) /\ [:{x},(proj2 (dom f)):]) & dom g c= proj2 (dom f) & rng g c= rng f & ( for y being object st y in dom g holds
( g . y = f . (x,y) & [x,y] in dom f ) ) )

proof end;

theorem Th25: :: FUNCT_5:32

for X, Y being set
for y being object
for f being Function st [:X,Y:] <> {} & dom f = [:X,Y:] & y in Y holds
ex g being Function st
( (curry' f) . y = g & dom g = X & rng g c= rng f & ( for x being object st x in X holds
g . x = f . (x,y) ) )

proof end;

theorem :: FUNCT_5:33

for x being object
for f being Function st x in dom (curry' f) holds
(curry' f) . x is Function by Th23;

theorem :: FUNCT_5:34

for x being object
for f, g being Function st x in dom (curry' f) & g = (curry' f) . x holds
( dom g = proj1 ((dom f) /\ [:(proj1 (dom f)),{x}:]) & dom g c= proj1 (dom f) & rng g c= rng f & ( for y being object st y in dom g holds
( g . y = f . (y,x) & [y,x] in dom f ) ) )

proof end;

theorem Th28: :: FUNCT_5:35

for X, Y being set
for f being Function st dom f = [:X,Y:] holds
( rng (curry f) c= Funcs (Y,(rng f)) & rng (curry' f) c= Funcs (X,(rng f)) )

proof end;

theorem :: FUNCT_5:36

for f being Function holds
( rng (curry f) c= PFuncs ((proj2 (dom f)),(rng f)) & rng (curry' f) c= PFuncs ((proj1 (dom f)),(rng f)) )

proof end;

theorem Th30: :: FUNCT_5:37

for X, Y being set
for f being Function st rng f c= PFuncs (X,Y) holds
( dom (uncurry f) c= [:(dom f),X:] & dom (uncurry' f) c= [:X,(dom f):] )

proof end;

theorem Th31: :: FUNCT_5:38

for x, y being object
for f, g being Function st x in dom f & g = f . x & y in dom g holds
( [x,y] in dom (uncurry f) & (uncurry f) . (x,y) = g . y & g . y in rng (uncurry f) )

proof end;

theorem :: FUNCT_5:39

for x, y being object
for f, g being Function st x in dom f & g = f . x & y in dom g holds
( [y,x] in dom (uncurry' f) & (uncurry' f) . (y,x) = g . y & g . y in rng (uncurry' f) )

proof end;

theorem Th33: :: FUNCT_5:40

for X, Y being set
for f being Function st rng f c= PFuncs (X,Y) holds
( rng (uncurry f) c= Y & rng (uncurry' f) c= Y )

proof end;

theorem Th34: :: FUNCT_5:41

for X, Y being set
for f being Function st rng f c= Funcs (X,Y) holds
( rng (uncurry f) c= Y & rng (uncurry' f) c= Y )

proof end;

theorem Th35: :: FUNCT_5:42

( curry {} = {} & curry' {} = {} ) by Def1, Th1;

theorem Th36: :: FUNCT_5:43

( uncurry {} = {} & uncurry' {} = {} )

proof end;

theorem Th37: :: FUNCT_5:44

for X, Y being set
for f1, f2 being Function st dom f1 = [:X,Y:] & dom f2 = [:X,Y:] & curry f1 = curry f2 holds
f1 = f2

proof end;

theorem Th38: :: FUNCT_5:45

for X, Y being set
for f1, f2 being Function st dom f1 = [:X,Y:] & dom f2 = [:X,Y:] & curry' f1 = curry' f2 holds
f1 = f2

proof end;

theorem Th39: :: FUNCT_5:46

for X, Y being set
for f1, f2 being Function st rng f1 c= Funcs (X,Y) & rng f2 c= Funcs (X,Y) & X <> {} & uncurry f1 = uncurry f2 holds
f1 = f2

proof end;

theorem :: FUNCT_5:47

for X, Y being set
for f1, f2 being Function st rng f1 c= Funcs (X,Y) & rng f2 c= Funcs (X,Y) & X <> {} & uncurry' f1 = uncurry' f2 holds
f1 = f2

proof end;

theorem Th41: :: FUNCT_5:48

for X, Y being set
for f being Function st rng f c= Funcs (X,Y) & X <> {} holds
( curry (uncurry f) = f & curry' (uncurry' f) = f )

proof end;

theorem :: FUNCT_5:49

for X, Y being set
for f being Function st dom f = [:X,Y:] holds
( uncurry (curry f) = f & uncurry' (curry' f) = f )

proof end;

theorem Th43: :: FUNCT_5:50

for X, Y being set
for f being Function st dom f c= [:X,Y:] holds
( uncurry (curry f) = f & uncurry' (curry' f) = f )

proof end;

theorem Th44: :: FUNCT_5:51

for X, Y being set
for f being Function st rng f c= PFuncs (X,Y) & not {} in rng f holds
( curry (uncurry f) = f & curry' (uncurry' f) = f )

proof end;

theorem :: FUNCT_5:52

for X, Y being set
for f1, f2 being Function st dom f1 c= [:X,Y:] & dom f2 c= [:X,Y:] & curry f1 = curry f2 holds
f1 = f2

proof end;

theorem :: FUNCT_5:53

for X, Y being set
for f1, f2 being Function st dom f1 c= [:X,Y:] & dom f2 c= [:X,Y:] & curry' f1 = curry' f2 holds
f1 = f2

proof end;

theorem :: FUNCT_5:54

for X, Y being set
for f1, f2 being Function st rng f1 c= PFuncs (X,Y) & rng f2 c= PFuncs (X,Y) & not {} in rng f1 & not {} in rng f2 & uncurry f1 = uncurry f2 holds
f1 = f2

proof end;

theorem :: FUNCT_5:55

for X, Y being set
for f1, f2 being Function st rng f1 c= PFuncs (X,Y) & rng f2 c= PFuncs (X,Y) & not {} in rng f1 & not {} in rng f2 & uncurry' f1 = uncurry' f2 holds
f1 = f2

proof end;

theorem Th49: :: FUNCT_5:56

for X, Y, Z being set st X c= Y holds
Funcs (Z,X) c= Funcs (Z,Y)

proof end;

theorem Th50: :: FUNCT_5:57

for X being set holds Funcs ({},X) = {{}}

proof end;

theorem :: FUNCT_5:58

for X being set
for x being object holds
( X, Funcs ({x},X) are_equipotent & card X = card (Funcs ({x},X)) )

proof end;

theorem Th52: :: FUNCT_5:59

for X being set
for x being object holds Funcs (X,{x}) = {(X --> x)}

proof end;

theorem Th53: :: FUNCT_5:60

for X1, X2, Y1, Y2 being set st X1,Y1 are_equipotent & X2,Y2 are_equipotent holds
( Funcs (X1,X2), Funcs (Y1,Y2) are_equipotent & card (Funcs (X1,X2)) = card (Funcs (Y1,Y2)) )

proof end;

theorem :: FUNCT_5:61

for X1, X2, Y1, Y2 being set st card X1 = card Y1 & card X2 = card Y2 holds
card (Funcs (X1,X2)) = card (Funcs (Y1,Y2))

proof end;

theorem :: FUNCT_5:62

for X, X1, X2 being set st X1 misses X2 holds
( Funcs ((X1 \/ X2),X),[:(Funcs (X1,X)),(Funcs (X2,X)):] are_equipotent & card (Funcs ((X1 \/ X2),X)) = card [:(Funcs (X1,X)),(Funcs (X2,X)):] )

proof end;

theorem :: FUNCT_5:63

for X, Y, Z being set holds
( Funcs ([:X,Y:],Z), Funcs (X,(Funcs (Y,Z))) are_equipotent & card (Funcs ([:X,Y:],Z)) = card (Funcs (X,(Funcs (Y,Z)))) )

proof end;

theorem :: FUNCT_5:64

for X, Y, Z being set holds
( Funcs (Z,[:X,Y:]),[:(Funcs (Z,X)),(Funcs (Z,Y)):] are_equipotent & card (Funcs (Z,[:X,Y:])) = card [:(Funcs (Z,X)),(Funcs (Z,Y)):] )

proof end;

theorem :: FUNCT_5:65

for X being set
for x, y being object st x <> y holds
( Funcs (X,{x,y}), bool X are_equipotent & card (Funcs (X,{x,y})) = card (bool X) )

proof end;

theorem :: FUNCT_5:66

for X being set
for x, y being object st x <> y holds
( Funcs ({x,y},X),[:X,X:] are_equipotent & card (Funcs ({x,y},X)) = card [:X,X:] )

proof end;

notation

synonym op0 for 0 ;

end;

definition

:: original: op0
redefine func op0 -> Element of {0};
coherence
op0 is Element of {0} by TARSKI:def 1;

end;

definition

func op1 -> set equals :: FUNCT_5:def 5
0 .--> 0;

coherence
0 .--> 0 is set ;

func op2 -> set equals :: FUNCT_5:def 6
(0,0) :-> 0;

coherence
(0,0) :-> 0 is set ;

end;

:: deftheorem defines op1 FUNCT_5:def 5 :
op1 = 0 .--> 0;

:: deftheorem defines op2 FUNCT_5:def 6 :
op2 = (0,0) :-> 0;

definition

:: original: op1
redefine func op1 -> UnOp of {0};
coherence
op1 is UnOp of {0} ;
:: original: op2
redefine func op2 -> BinOp of {0};
coherence
op2 is BinOp of {0} ;

end;

definition

let D be non empty set ;
let X be set ;
let E be non empty set ;
let F be FUNCTION_DOMAIN of X,E;
let f be Function of D,F;
let d be Element of D;
:: original: .
redefine func f . d -> Element of F;
coherence
f . d is Element of F

proof end;

end;

theorem Th60: :: FUNCT_5:67

for C, D, E being non empty set
for f being Function of [:C,D:],E holds curry f is Function of C,(Funcs (D,E))

proof end;

theorem Th61: :: FUNCT_5:68

for C, D, E being non empty set
for f being Function of [:C,D:],E holds curry' f is Function of D,(Funcs (C,E))

proof end;

definition

let C, D, E be non empty set ;
let f be Function of [:C,D:],E;
:: original: curry
redefine func curry f -> Function of C,(Funcs (D,E));
coherence
curry f is Function of C,(Funcs (D,E)) by Th60;
:: original: curry'
redefine func curry' f -> Function of D,(Funcs (C,E));
coherence
curry' f is Function of D,(Funcs (C,E)) by Th61;

end;

theorem :: FUNCT_5:69

for C, D, E being non empty set
for c being Element of C
for d being Element of D
for f being Function of [:C,D:],E holds f . (c,d) = ((curry f) . c) . d

proof end;

theorem :: FUNCT_5:70

for C, D, E being non empty set
for c being Element of C
for d being Element of D
for f being Function of [:C,D:],E holds f . (c,d) = ((curry' f) . d) . c

proof end;

:: from ISOCAT_2, 2011.11.25, A.T.

definition

let A, B, C be non empty set ;
let f be Function of A,(Funcs (B,C));
:: original: uncurry
redefine func uncurry f -> Function of [:A,B:],C;
coherence
uncurry f is Function of [:A,B:],C

proof end;

end;

theorem :: FUNCT_5:71

for A, B, C being non empty set
for f being Function of A,(Funcs (B,C)) holds curry (uncurry f) = f

proof end;

theorem :: FUNCT_5:72

for A, B, C being non empty set
for f being Function of A,(Funcs (B,C))
for a being Element of A
for b being Element of B holds (uncurry f) . (a,b) = (f . a) . b

proof end;