
theorem lem24:
  for t being Integer st t divides 24 holds
  t=-1 or t=1 or t=-2 or t=2 or t=-3 or t=3 or t=-4 or t=4 or t=-6 or t=6
  or t=-8 or t=8 or t=-12 or t=12 or t=-24 or t=24
proof
  let t be Integer;
  reconsider n=|.t.| as Nat;
  assume t divides 24;
  then n divides |.24.| by INT_2:16;
  then n divides 24;
  then n=1 or n=2 or n=3 or n=4 or n=6 or n=8 or n=12 or n=24 by lem24nat;
  hence t=-1 or t=1 or t=-2 or t=2 or t=-3 or t=3 or t=-4 or t=4 or t=-6 or t=6
  or t=-8 or t=8 or t=-12 or t=12 or t=-24 or t=24 by lemmod;
end;
