theorem Th2:
  m |-> (n |-> x) is tabular
proof
  set s=m |-> (n |-> x);
  reconsider n1=n as Nat;
  take n1;
  let z;
  assume
A1: z in rng s;
  take n|->x;
  rng s c= {n |-> x} by FUNCOP_1:13;
  hence thesis by A1,CARD_1:def 7,TARSKI:def 1;
end;
