let R be Ring; :: thesis: for V being RightMod of R
for v being Vector of V holds Sum {v} = v
let V be RightMod of R; :: thesis: for v being Vector of V holds Sum {v} = v
let v be Vector of V; :: thesis: Sum {v} = v
A1: Sum <*v*> = v by RLVECT_1:61;
( rng <*v*> = {v} & <*v*> is one-to-one ) by FINSEQ_1:56, FINSEQ_3:102;
hence Sum {v} = v by A1, Def3; :: thesis: verum