let R be Ring; :: thesis: for V being RightMod of R
for W1, W2 being Submodule of V holds 0. W1 in W2
let V be RightMod of R; :: thesis: for W1, W2 being Submodule of V holds 0. W1 in W2
let W1, W2 be Submodule of V; :: thesis: 0. W1 in W2
0. W1 = 0. V by Def2;
hence 0. W1 in W2 by Th17; :: thesis: verum