The papers contained in this volume were presented at the fourth edition of the IFIP International Conference on Theoretical Computer Science (IFIP TCS), held August 23-24, 2006 in Santiago, Chile. They were selected from 44 pa- pers submitted from 17 countries in response to the call for papers. A total of 16 submissions were accepted as full papers, yielding an acceptance rate of about 36%. Papers sohcited for IFIP TCS 2006 were meant to constitute orig- inal contributions in two general areas: Algorithms, Complexity and Models of Computation; and Logic, Semantics, Specification and...

The papers contained in this volume were presented at the fourth edition of the IFIP International Conference on Theoretical Computer Science (IFIP TCS), held August 23-24, 2006 in Santiago, Chile. They were selected from 44 pa- pers submitted from 17 countries in response to the call for papers. A total of 16 submissions were accepted as full papers, yielding an acceptance rate of about 36%. Papers sohcited for IFIP TCS 2006 were meant to constitute orig- inal contributions in two general areas: Algorithms, Complexity and Models of Computation; and Logic, Semantics, Specification and...

Integrity constraints are semantic conditions that a database should satisfy in order to be an appropriate model of external reality. In practice, and for many reasons, a database may not satisfy those integrity constraints, and for that reason it is said to be inconsistent. However, and most likely, a large portion of the database is still semantically correct, in a sense that has to be made precise. After having provided a formal characterization of consistent data in an inconsistent database, the natural problem emerges of extracting that semantically correct data, as query answers. The...