reserve a,b,k,m,n,s for Nat;
reserve c,c1,c2,c3 for Complex;
reserve i,j,z for Integer;
reserve p for Prime;
reserve x for object;

theorem Th36:
  {k where k is Nat: k divides 5|^n} = divisors(5|^n,4,1)
  proof
    set A = {k where k is Nat: k divides 5|^n};
    set B = divisors(5|^n,4,1);
    thus A c= B
    proof
      let x be object;
      assume x in A;
      then consider k such that
A1:   x = k and
A2:   k divides 5|^n;
      k mod 4 = 1 by A2,Th34;
      hence thesis by A1,A2;
    end;
    let x be object;
    assume x in B;
    then ex k st x = k & k mod 4 = 1 & k divides 5|^n;
    hence thesis;
  end;
