theorem Th10: :: VECTSP10:10

for K being non empty right_complementable Abelian add-associative right_zeroed well-unital distributive associative doubleLoopStr
for V being VectSp of K
for W1, W2 being Subspace of V st V is_the_direct_sum_of W1,W2 holds
for v being Vector of V st v in W2 holds
v |-- (W1,W2) = [(0. V),v]