reserve a,b,i,k,m,n for Nat;
reserve s,z for non zero Nat;
reserve r for Real;
reserve c for Complex;
reserve e1,e2,e3,e4,e5 for ExtReal;

theorem Th4:
  3|^10+1 = 5905 * 10
  proof
    thus 3|^10+1 = 3*3*3*3*3*3*3*3*3*3+1 by NUMBER02:6
    .= 5905 * 10;
  end;
