reserve n for Nat;

theorem
  for f be non empty FinSequence of TOP-REAL 2 for p be Point of
  TOP-REAL 2 holds len R_Cut(f,p) >= 1
proof
  let f be non empty FinSequence of TOP-REAL 2;
  let p be Point of TOP-REAL 2;
  R_Cut(f,p) <> {} by JORDAN1J:44;
  then
A1: len R_Cut(f,p) > 0 by NAT_1:3;
  1 = 0+1;
  hence thesis by A1,NAT_1:13;
end;
