:: deftheorem BLDef4 defines - ZMATRLIN:def 15 :
for V, W being non empty ModuleStr over INT.Ring
for f, b₄ being Form of V,W holds
( b₄ = - f iff for v being Vector of V
for w being Vector of W holds b₄ . (v,w) = - (f . (v,w)) );