theorem
  for V being non empty CLSStruct, M being Subset of V, N being convex
  Subset of V st M c= N holds conv M c= N
proof
  let V be non empty CLSStruct;
  let M be Subset of V;
  let N be convex Subset of V;
  assume M c= N;
  then N in Convex-Family M by Def25;
  hence thesis by SETFAM_1:3;
end;
