let x be set ; :: thesis: for R being Ring
for V being RightMod of R
for W being Submodule of V st x in W holds
x in V

let R be Ring; :: thesis: for V being RightMod of R
for W being Submodule of V st x in W holds
x in V

let V be RightMod of R; :: thesis: for W being Submodule of V st x in W holds
x in V

let W be Submodule of V; :: thesis: ( x in W implies x in V )
assume x in W ; :: thesis: x in V
then ( x in the carrier of W & the carrier of W c= the carrier of V ) by Def2, STRUCT_0:def 5;
hence x in V by STRUCT_0:def 5; :: thesis: verum