ABSTRACT
The proof of the reverse implication is indirect (as are all such completeness proofs): I shall show that if M = $ v is not derivable, i.e . if pd* M D*pcj(v) is not ep in F d, then there is an B in A d and a homomorphism h into B w ith h(m) = eg for m in M and h (u )^ eg . The algebra B will be a quotient alge bra of F d and h the canonical homomorphism onto B .
