reserve r,s,t,u for Real;

theorem
  for V being non empty RLSStruct, F being convex-membered Subset-Family
  of V holds meet F is convex
proof
  let V be non empty RLSStruct, F be convex-membered Subset-Family of V;
  for M being Subset of V st M in F holds M is convex by Def3;
  hence thesis by CONVEX1:15;
end;
