:: deftheorem Def18 defines feasible FUNCTOR0:def 18 :
for C1, C2 being non empty AltGraph
for F being Covariant FunctorStr over C1,C2 holds
( F is feasible iff for o1, o2 being Object of C1 st <^o1,o2^> <> {} holds
<^(F . o1),(F . o2)^> <> {} );