Logic Colloquium '98 : proceedings of the Annual European Summer Meeting of the Association for Symbolic Logic, held in Prague, Czech Republic, August 9-15, 1998

A compilation of papers presented at the 1998 European Summer Meeting of the Association for Symbolic Logic, Logic Colloquium '98 includes surveys and research from the world's preeminent logicians. Topics cover current research from all areas of mathematical logic, including Proof Theory, Set Theory, Model Theory, Computability Theory, and Philosophy. This book will be of interest to students and researchers of mathematical logic. Summary. For reducibilities r and r' such that r is weaker than r', we say that the r-degree of A, i.e., the class of sets which are r-equivalent to A, collapses to the r'-degree of A if both degrees coincide. The proceedings of the Logic Colloquium '98 with papers covering current research from all areas of mathematical logic, including Proof Theory, Set Theory, Model Theory, Computability Theory, and Philosophy.