
theorem Th12:
  for V being RealLinearSpace, M being Subset of V, N being
  circled Subset of V st M c= N holds Cir M c= N
proof
  let V be RealLinearSpace, M be Subset of V, N be circled Subset of V;
  assume M c= N;
  then N in Circled-Family M by Def2;
  hence thesis by SETFAM_1:3;
end;
