reserve V for RealLinearSpace;
reserve W,W1,W2,W3 for Subspace of V;
reserve u,u1,u2,v,v1,v2 for VECTOR of V;
reserve a,a1,a2 for Real;
reserve X,Y,x,y,y1,y2 for set;

theorem Th14:
  W1 /\ W2 = W2 /\ W1
proof
  the carrier of W1 /\ W2 = (the carrier of W2) /\ (the carrier of W1) by Def2;
  hence thesis by Def2;
end;
