let V, W be non empty right_zeroed ModuleStr over INT.Ring ; :: thesis: for f being additiveSAF Form of V,W
for w being Vector of W holds f . ((0. V),w) = 0
let f be additiveSAF Form of V,W; :: thesis: for w being Vector of W holds f . ((0. V),w) = 0
let v be Vector of W; :: thesis: f . ((0. V),v) = 0
f . ((0. V),v) = f . (((0. V) + (0. V)),v) by RLVECT_1:def 4
.= (f . ((0. V),v)) + (f . ((0. V),v)) by BLTh26 ;
hence f . ((0. V),v) = 0 ; :: thesis: verum