“…From (8), the even subalgebras of Cl(V , Q) and Cl(V , Q, c ) coincide (as algebras), as do their odd parts (as vector spaces). Our quest for going over to projective space on Cl(V , Q) comes from an observation resulting from (35): for all homogeneous elements p, q ∈ Cl(V , Q), we have F (pq) = F (p c q) despite the fact that their products pq and p c q need not coincide. From (11), Theorems 6.2, 6.3 and Remark 6.4 we readily obtain: Corollary 6.6.…”