theorem Th66: :: VECTSP_4:66

for GF being non empty right_complementable well-unital distributive Abelian add-associative right_zeroed associative doubleLoopStr
for V being non empty right_complementable vector-distributive scalar-distributive scalar-associative scalar-unital Abelian add-associative right_zeroed ModuleStr over GF
for v being Element of V
for W1, W2 being strict Subspace of V holds
( v + W1 = v + W2 iff W1 = W2 )