let A be non empty AltGraph ; for o1, o2 being Object of A st <^o1,o2^> <> {} holds
for F being feasible Covariant FunctorStr over A,A st F = id A holds
for m being Morphism of o1,o2 holds F . m = m
let o1, o2 be Object of A; ( <^o1,o2^> <> {} implies for F being feasible Covariant FunctorStr over A,A st F = id A holds
for m being Morphism of o1,o2 holds F . m = m )
assume A1:
<^o1,o2^> <> {}
; for F being feasible Covariant FunctorStr over A,A st F = id A holds
for m being Morphism of o1,o2 holds F . m = m
let F be feasible Covariant FunctorStr over A,A; ( F = id A implies for m being Morphism of o1,o2 holds F . m = m )
assume A2:
F = id A
; for m being Morphism of o1,o2 holds F . m = m
let m be Morphism of o1,o2; F . m = m
<^(F . o1),(F . o2)^> <> {}
by A1, Def18;
hence F . m =
(Morph-Map (F,o1,o2)) . m
by A1, Def15
.=
m
by A1, A2, Th30
;
verum