Abstract:
This paper is a general introduction to Positive Logic, where
only what we call h-inductive sentences are under consideration, allowing
the extension to homomorphisms of model-theoric notions which are
classically associated to embeddings; in particular, the existentially closed
models, that were primitively defined by Abraham Robinson, become here
positively closed models. It accounts for recent results in this domain, and
is oriented towards the positivisation of Jonsson theories.
