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The Härtig quantifier: a survey

Published online by Cambridge University Press:  12 March 2014

Heinrich Herre
Affiliation:
Sektion Informatik, Universität Leipzig, O-7010 Leipzig, Germany
Michał Krynicki
Affiliation:
Institute of Mathematics, University of Warsaw, 00-901 Warsaw, Poland
Alexandr Pinus
Affiliation:
Novosibirsk Electrotechnical Institute, Novosibirsk, USSR
Jouko Väänänen
Affiliation:
Department of Mathematics, University of Helsinki, 00100 Helsinki, Finland

Abstract

A fundamental notion in a large part of mathematics is the notion of equicardinality. The language with Härtig quantifier is, roughly speaking, a first-order language in which the notion of equicardinality is expressible. Thus this language, denoted by LI, is in some sense very natural and has in consequence special interest. Properties of LI are studied in many papers. In [BF, Chapter VI] there is a short survey of some known results about LI. We feel that a more extensive exposition of these results is needed.

The aim of this paper is to give an overview of the present knowledge about the language LI and list a selection of open problems concerning it.

After the Introduction (§1), in §§2 and 3 we give the fundamental results about LI. In §4 the known model-theoretic properties are discussed. The next section is devoted to properties of mathematical theories in LI. In §6 the spectra of sentences of LI are discussed, and §7 is devoted to properties of LI which depend on set-theoretic assumptions. The paper finishes with a list of open problem and an extensive bibliography. The bibliography contains not only papers we refer to but also all papers known to us containing results about the language with Härtig quantifier.

Contents. §1. Introduction. §2. Preliminaries. §3. Basic results. §4. Model-theoretic properties of LI. §5. Decidability of theories with I. §6. Spectra of LI-sentences. §7. Independence results. §8. What is not yet known about LI. Bibliography.

Information

Type
Survey/expository paper
Copyright
Copyright © Association for Symbolic Logic 1991

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