reserve X for set;
reserve a,b,c,k,m,n for Nat;
reserve i,j for Integer;
reserve r,s for Real;
reserve p,p1,p2,p3 for Prime;
reserve z for Complex;

theorem
  Fermat m = Fermat n implies m = n
  proof
    assume Fermat m = Fermat n;
    then 2 |^ m = 2 |^ n by PEPIN:30;
    hence m = n by PEPIN:30;
  end;
