reserve D,D9 for non empty set;
reserve R for Ring;
reserve G,H,S for non empty ModuleStr over R;
reserve UN for Universe;
reserve R for Ring;
reserve G, H for LeftMod of R;
reserve G1, G2, G3 for LeftMod of R;
reserve f for LModMorphismStr over R;
reserve a,b,c for Element of {0,1,2};

theorem Th28:
  for f being Function of D,D9 st D in UN & D9 in UN holds f in UN
proof
  let f be Function of D,D9;
  assume D in UN & D9 in UN;
  then
A1: Funcs(D,D9) in UN by CLASSES2:61;
  f in Funcs(D,D9) by FUNCT_2:8;
  hence thesis by A1,ORDINAL1:10;
end;
