
theorem NF992:
  for n being Nat st n is odd holds 1 <= n & (n + 1) div 2 = (n + 1) / 2
  proof
    let n be Nat;
    assume L010: n is odd; then
    0 < 0 + n;
    hence 1 <= n by NAT_1:19;
    thus (n + 1) div 2 = (n + 1) / 2 by L010,NAT_6:4;
  end;
