This is a thoroughly revised and enlarged second edition that presents the main results of descriptive complexity theory, that is, the connections between axiomatizability of classes of finite structures and their complexity with respect to time and space bounds. The logics that are important in this context include fixed-point logics, transitive closure logics, and also certain infinitary languages; their model theory is studied in full detail. The book is written in such a way that the respective parts on model theory and descriptive complexity theory may be read independently.

The 1999 Annual Conference of the European Association for Computer Science Logic, CSL'99, was held in Madrid, Spain, on September 20-25, 1999. CSL'99 was the 13th in a series of annual meetings, originally intended as Internat- nal Workshops on Computer Science Logic, and the 8th to be held as the - nual Conference of the EACSL. The conference was organized by the Computer Science Departments (DSIP and DACYA) at Universidad Complutense in M- rid (UCM). The CSL'99 program committee selected 34 of 91 submitted papers for p- sentation at the conference and publication in this proceedings volume. Each submitted paper was refereed by at least two, and in almost all cases, three di erent referees. The second refereeing round, previously required before a - per was accepted for publication in the proceedings, was dropped following a decision taken by the EACSL membership meeting held during CSL'98 (Brno, Czech Republic, August 25, 1998).

This introduction to first-order logic clearly works out the role of first-order logic in the foundations of mathematics, particularly the two basic questions of the range of the axiomatic method and of theorem-proving by machines. It covers several advanced topics not commonly treated in introductory texts, such as Fraisse's characterization of elementary equivalence, Lindstroem's theorem on the maximality of first-order logic, and the fundamentals of logic programming.

Was ist ein mathematischer Beweis? Wie lassen sich Beweise rechtfertigen? Gibt es Grenzen der Beweisbarkeit? Ist die Mathematik widerspruchsfrei? Kann man das Auffinden mathematischer Beweise Computern ubertragen? Erst im 20. Jahrhundert ist es der mathematischen Logik gelungen, weitreichende Antworten auf diese Fragen zu geben: Im vorliegenden Werk werden die Ergebnisse systematisch zusammengestellt; im Mittelpunkt steht dabei die Logik erster Stufe. Die Lekture setzt - ausser einer gewissen Vertrautheit mit der mathematischen Denkweise - keine spezifischen Kenntnisse voraus. In der vorliegenden 5. Auflage finden sich erstmals Loesungsskizzen zu den Aufgaben.

This introduction to first-order logic clearly works out the role of first-order logic in the foundations of mathematics, particularly the two basic questions of the range of the axiomatic method and of theorem-proving by machines. It covers several advanced topics not commonly treated in introductory texts, such as Fraisse's characterization of elementary equivalence, Lindstroem's theorem on the maximality of first-order logic, and the fundamentals of logic programming.