:: deftheorem Def3 defines Ort_Comp RUSUB_5:def 3 :
for V being RealUnitarySpace
for W being Subspace of V
for b₃ being strict Subspace of V holds
( b₃ = Ort_Comp W iff the carrier of b₃ = { v where v is VECTOR of V : for w being VECTOR of V st w in W holds
w,v are_orthogonal } );