hereby :: thesis: ( ( for o1, o2 being object of C1 st <^o1,o2^> <> {} holds
<^(F . o1),(F . o2)^> <> {} ) implies F is feasible )
assume A1: F is feasible ; :: thesis: for o1, o2 being object of C1 st <^o1,o2^> <> {} holds
<^(F . o1),(F . o2)^> <> {}

let o1, o2 be object of C1; :: thesis: ( <^o1,o2^> <> {} implies <^(F . o1),(F . o2)^> <> {} )
assume A2: <^o1,o2^> <> {} ; :: thesis: <^(F . o1),(F . o2)^> <> {}
<^(F . o1),(F . o2)^> = the Arrows of C2 . (F . o1),(F . o2) by ALTCAT_1:def 2
.= the Arrows of C2 . (the ObjectMap of F . o1,o2) by Th23 ;
hence <^(F . o1),(F . o2)^> <> {} by A1, A2, Def12; :: thesis: verum
end;
assume A3: for o1, o2 being object of C1 st <^o1,o2^> <> {} holds
<^(F . o1),(F . o2)^> <> {} ; :: thesis: F is feasible
let o1, o2 be object of C1; :: according to FUNCTOR0:def 12 :: thesis: ( <^o1,o2^> <> {} implies the Arrows of C2 . (the ObjectMap of F . o1,o2) <> {} )
assume A4: <^o1,o2^> <> {} ; :: thesis: the Arrows of C2 . (the ObjectMap of F . o1,o2) <> {}
<^(F . o1),(F . o2)^> = the Arrows of C2 . (F . o1),(F . o2) by ALTCAT_1:def 2
.= the Arrows of C2 . (the ObjectMap of F . o1,o2) by Th23 ;
hence the Arrows of C2 . (the ObjectMap of F . o1,o2) <> {} by A3, A4; :: thesis: verum