reserve V for non empty set,
  A,B,A9,B9 for Element of V;
reserve f,f9 for Element of Funcs(V);
reserve m,m1,m2,m3,m9 for Element of Maps V;

theorem Th16:
  m in Maps(A,B) implies m = [[A,B],m`2]
proof
  assume m in Maps(A,B);
  then
A1: ex f being Element of Funcs(V) st m = [[A,B],f] & [[A,B],f] in Maps( V);
  thus thesis by A1;
end;
