We study the groups GalL(T ) and GalKP (T ), and the associated equivalence relations EL and EKP , attached to a first order theory T . An example is given where EL 6= EKP (a non G-compact theory).â€¦ (More)

This paper is a contribution to the study of equality-free logic, that is, first-order logic without equality. We mainly devote ourselves to the study of algebraic characterizations of its relationâ€¦ (More)

I present a notion of invariance under arbitrary surjective mappings for operators on a relational finite type hierarchy generalizing the so called Tarski-Sher criterion for logicality and Iâ€¦ (More)

We continue work of Shelah on the cardinality of families of pairwise incompatible types in simple theories obtaining characterizations of simple and supersimple theories. WC develop a local analysisâ€¦ (More)

There is a model-completion Tn of the theory of a (reflexive) ncoloured graph ã€ˆX,R1, . . . , Rnã€‰ such that Rn is total, and Ri â—¦Rj âŠ† Ri+j for all i, j. For n > 2, the theory Tn is not simple, andâ€¦ (More)

We prove a property of generic homogeneity of tuples starting an infinite indiscernible sequence in a simple theory and we use it to give a shorter proof of the Independence Theorem for Lascar strongâ€¦ (More)

We prove that every many-sorted Ï‰-categorical theory is completely interpretable in a one-sorted Ï‰-categorical theory. As an application, we give a short proof of the existence of non Gâ€“compactâ€¦ (More)