
theorem Th9: :: Clique37:
for R being RelStr, C being Clique of R, S being Subset of C
  holds S is Clique of R
proof
  let R be RelStr, C be Clique of R, S be Subset of C;
  set iR = the InternalRel of R;
A1: iR is_connected_in C by Def1;
  iR is_connected_in S by A1;
  hence thesis by Def1,XBOOLE_1:1;
end;
