
theorem
  for S being non void non degenerated TopStruct for L being Block of S
  ex x being Point of S st not x in L
proof
  let S be non void non degenerated TopStruct;
  let L be Block of S;
A1: L in the topology of S;
  now
    assume [#]S c= L;
    then [#]S=L by A1;
    hence contradiction by PENCIL_1:def 5;
  end;
  then consider x being object such that
A2: x in [#]S and
A3: not x in L;
  reconsider x as Point of S by A2;
  take x;
  thus thesis by A3;
end;
