  How can non-classical logic contribute to the analysis of complexity in
computer science? In this paper, we give a step towards this question, taking a
logical model-theoretic approach to the analysis of complexity in fuzzy
constraint satisfaction. We study fuzzy positive-primitive sentences, and we
present an algebraic characterization of classes axiomatized by this kind of
sentences in terms of homomorphisms and direct products. The ultimate goal is
to study the expressiveness and reasoning mechanisms of non-classical
languages, with respect to constraint satisfaction problems and, in general, in
modelling decision scenarios. fuzzy constraint satisfaction, fuzzy logics,
model theory.
