let C be Category; for b, a being Object of C
for f being Morphism of C st b is terminal & dom f = a & cod f = b holds
term a,b = f
let b, a be Object of C; for f being Morphism of C st b is terminal & dom f = a & cod f = b holds
term a,b = f
let f be Morphism of C; ( b is terminal & dom f = a & cod f = b implies term a,b = f )
assume that
A1:
b is terminal
and
A2:
( dom f = a & cod f = b )
; term a,b = f
consider h being Morphism of a,b such that
A3:
for g being Morphism of a,b holds h = g
by A1, CAT_1:def 15;
f is Morphism of a,b
by A2, CAT_1:22;
hence f =
h
by A3
.=
term a,b
by A3
;
verum