let D, C, E be non empty set ; for f being Function of [:C,D:],E holds curry' f is Function of D,(Funcs C,E)
let f be Function of [:C,D:],E; curry' f is Function of D,(Funcs C,E)
A1:
dom f = [:C,D:]
by FUNCT_2:def 1;
A2:
rng (curry' f) c= Funcs C,E
proof
A3:
rng (curry' f) c= Funcs C,
(rng f)
by A1, FUNCT_5:42;
let x be
set ;
TARSKI:def 3 ( not x in rng (curry' f) or x in Funcs C,E )
assume
x in rng (curry' f)
;
x in Funcs C,E
then consider g being
Function such that A4:
x = g
and A5:
dom g = C
and A6:
rng g c= rng f
by A3, FUNCT_2:def 2;
rng f c= E
by RELAT_1:def 19;
then
rng g c= E
by A6, XBOOLE_1:1;
then
g is
Function of
C,
E
by A5, FUNCT_2:def 1, RELSET_1:11;
hence
x in Funcs C,
E
by A4, FUNCT_2:11;
verum
end;
dom (curry' f) = D
by A1, FUNCT_5:31;
hence
curry' f is Function of D,(Funcs C,E)
by A2, FUNCT_2:def 1, RELSET_1:11; verum