reserve a,b,c,k,m,n for Nat;
reserve i,j for Integer;
reserve p for Prime;

theorem Th20:
  for r being ExtReal holds
  <* r *> is with_values_greater_or_equal_one implies r >= 1
  proof
    let r be ExtReal;
    rng <*r*> = {r} by FINSEQ_1:38;
    then r in rng <*r*> by TARSKI:def 1;
    hence thesis;
  end;
