theorem Th30:
  {} in V & a is initial implies a = {}
proof
  assume {} in V;
  then reconsider B = {} as Element of V;
  set b = @B;
  assume a is initial;
  then Hom(a,b) <> {};
  then Funcs(@a,@b) <> {} by Lm6;
  hence thesis;
end;
