Seidenberg's condition P.- Field extensions.- Dedekind domains.- Effective mathematics ¿ the computer algebra viewpoint.- On some open problems in constructive probability theory.- Consistency and independence results in intuitionistic set theory.- Errata.- Computability of ordinal recursion of type level two.- A constructive approach to classical mathematics.- Remarks on the notion of standard non-isomorphic natural number series.- Reflections on Bishop's philosophy of mathematics.- Formalizing constructive mathematics: Why and how?.- Independence of premisses and the free topos.- An intuitionistic infinitesimal calculus.- Liberal constructive set theory.- Locating metric complements in ?n.- A disjunctive decomposition theorem for classical theories.- Towards a constructive foundation for quantum mechanics.- About infinity, finiteness and finitization (in connection with the foundations of mathematics).- A class of theorems with valid constructive counterparts.- Rational constructive analysis.