Proceedings of the Logic Colloquium. Held in Aachen, July 18 23, 1983

Filters and ultrafilters over definable subsets of admissible ordinals.- Superinfinitesimals and the calculus of the generalized riemann integral.- Point-picking games and HFD's.- On homomorphism types of superatomic interval Boolean algebras.- Dectdable theories of pseudo-Algebraically closed fields.- Definability in power series rings of nonzero characteristic.- Convexity properties and algebraic closure operators.- Remarks on finitely based logics.- Monadicity in topological pseudo-boolean algebras.- Finite extensions of finite groups.- Constructing choice sequences from lawless sequences of neighbourhood functions.- Partitions and homogeneous sets for admissible ordinals.- Elimination of quantifiers for the theory of Archimedean ordered divisible groups in a logic with Ramsey quantifiers.- A proof-theoretic approach to non standard analysis (continued).- Interpretations and the model theory of the classical geometries.- On cantor-bendixson spectra containing (1,1) - I.- Abstract model-theory and nets of C*-algebras: Noncommutative interpolation and preservation properties.- A contribution to nonstandard teratology.- Model- and substructure complete theories of ordered Abelian groups.- Quantifier elimination and decision procedures for valued fields.- On ? 3 1 .

Contiguous R.E. Degrees.- Abstract construction of counterexamples in recursive graph theory.- Minimal degrees and 1-generic sets below 0?.- Undecidability and recursive equivalence II.- Logical syntax and computational complexity.- Subrecursive hierarchies via direct limits.- A star-finite relational semantics for parallel programs.- Between constructive and classical mathematics.- Partial closures and semantics of while: Towards an iteration-based theory of data types.- Toward logic tailored for computational complexity.- On a new notion of partial conservativity.- Finitely approximable sets.- A unified approach to constructive and recursive analysis.- On faithful interpretability.- Abstract recursion as a foundation for the theory of algorithms.- Some logical problems connected with a modular decomposition theory of automata.- Diophantine equations in a fragment of number theory.- Generalized rules for quantifiers and the completeness of the intuitionistic operators &, ?, ?, ?, ?, ?.- On subsets of the Skolem class of exponential polynomials.- Effective operators in a topological setting.- An axiomatization of the apartness fragment of the theory DLO+ of dense linear order.