reserve o,m for set;

theorem Th5:
  for a,b being Object of c1Cat(o,m), f being Morphism of c1Cat(o,m
  ) holds f in Hom(a,b)
proof
  let a,b be Object of c1Cat(o,m), f be Morphism of c1Cat(o,m);
  cod f = o by TARSKI:def 1;
  then
A1: cod f = b by TARSKI:def 1;
  dom f = o by TARSKI:def 1;
  then dom f = a by TARSKI:def 1;
  hence thesis by A1;
end;
