:: deftheorem defines epi ALTCAT_3:def 8 :
for C being non empty AltCatStr
for o1, o2 being Object of C
for A being Morphism of o1,o2 holds
( A is epi iff for o being Object of C st <^o2,o^> <> {} holds
for B, C being Morphism of o2,o st B * A = C * A holds
B = C );