let A, B, C be Category; for F being Functor of [:A,B:],C
for f being Morphism of A
for b being Object of B holds (F ?- f) . b = F . (f,(id b))
let F be Functor of [:A,B:],C; for f being Morphism of A
for b being Object of B holds (F ?- f) . b = F . (f,(id b))
let f be Morphism of A; for b being Object of B holds (F ?- f) . b = F . (f,(id b))
let b be Object of B; (F ?- f) . b = F . (f,(id b))
reconsider G = F as Function of [: the carrier' of A, the carrier' of B:], the carrier' of C ;
reconsider Ff = (curry G) . f as Function of the carrier' of B, the carrier' of C ;
A1:
id b = (IdMap B) . b
by ISOCAT_1:def 12;
F ?- (dom f) is_naturally_transformable_to F ?- (cod f)
by Th14;
then
F ?- (dom f) is_transformable_to F ?- (cod f)
;
hence (F ?- f) . b =
((curry (F,f)) * (IdMap B)) . b
by NATTRA_1:def 5
.=
Ff . (id b)
by A1, FUNCT_2:15
.=
F . (f,(id b))
by FUNCT_5:69
;
verum