Further remarks on the elementary theory of formal power series rings.- Elimination of quantifiers for non semi-simple rings of characteristic p.- The quantifier elimination problem for rings without nilpotent elements and for semi-simple rings.- Existentially closed modules: Types and prime models.- Rings of continuous functions: Decision problems.- Weak partition relations, finite games, and independence results in Peano arithmetic.- Hensel fields in equal characteristic p>0.- On polynomials over real closed rings.- Les corps faiblement algebriquement clos non separablement clos ont la propriete d¿independance.- Horn-theories of abelian groups.- Two orderings of the class of all countable models of peano arithmetic.- Ramsey quantifiers in arithmetic.- Computational complexity of decision problems in elementary number theory.- Some diophantine nullstellens¿e.- A tree analysis of unprovable combinatorial statements.- A hierarchy of cuts in models of arithmetic.- Cofinal extension preserves recursive saturation.- Some model theory and number theory for models of weak systems of arithmetic.- Applications of complexity theory to ?o-definability Problems in arithmetic.- Minimally saturated models.- Totally categorical theories: Structural properties and the non-finite axiomatizability.