let R be Ring; :: thesis: for V being RightMod of R
for v being Vector of V
for L1, L2 being Linear_Combination of V holds (L1 - L2) . v = (L1 . v) - (L2 . v)

let V be RightMod of R; :: thesis: for v being Vector of V
for L1, L2 being Linear_Combination of V holds (L1 - L2) . v = (L1 . v) - (L2 . v)

let v be Vector of V; :: thesis: for L1, L2 being Linear_Combination of V holds (L1 - L2) . v = (L1 . v) - (L2 . v)
let L1, L2 be Linear_Combination of V; :: thesis: (L1 - L2) . v = (L1 . v) - (L2 . v)
thus (L1 - L2) . v = (L1 . v) + ((- L2) . v) by Def9
.= (L1 . v) + (- (L2 . v)) by Th50
.= (L1 . v) - (L2 . v) by RLVECT_1:def 11 ; :: thesis: verum