let R be Ring; :: thesis: for V being RightMod of R
for u being Vector of V
for W being Submodule of V
for C being Coset of W holds
( u in C iff C = u + W )

let V be RightMod of R; :: thesis: for u being Vector of V
for W being Submodule of V
for C being Coset of W holds
( u in C iff C = u + W )

let u be Vector of V; :: thesis: for W being Submodule of V
for C being Coset of W holds
( u in C iff C = u + W )

let W be Submodule of V; :: thesis: for C being Coset of W holds
( u in C iff C = u + W )

let C be Coset of W; :: thesis: ( u in C iff C = u + W )
thus ( u in C implies C = u + W ) :: thesis: ( C = u + W implies u in C )
proof
assume A1: u in C ; :: thesis: C = u + W
ex v being Vector of V st C = v + W by Def6;
hence C = u + W by A1, Th53; :: thesis: verum
end;
thus ( C = u + W implies u in C ) by Th44; :: thesis: verum