Tarek Sayed AHMED
A b s t r a c t. We review, and in the process unify and generalize, two techniques (due to N\'emeti and Pigozzi) for proving results concerning strong amalgamation in algebraic logic. Presenting them in a functorial context as adjoint situations, we show that both techniques can be seen as instances of the use of the Keisler-Shelah ultrapower Theorem in proving Robinson's Joint Consistency Theorem. Some new applications are given.