Ultraproduct invariant logics
نویسندگان
چکیده
منابع مشابه
The Ultraproduct Construction
This is a brief survey of the ultraproduct construction, which is meant to provide background material for the readers of this volume.
متن کاملLower bounds for invariant queries in logics with counting
We study the expressive power of counting logics in the presence of auxiliary relations such as orders and preorders. The simplest such logic, rst-order with counting, captures the complexity class TC 0 over ordered structures. We also consider rst-order logic with arbitrary unary quantiiers, and innnitary extensions. We start by giving a simple direct proof that rst-order with counting, in the...
متن کاملA Survey of Ultraproduct Constructions in General Topology
This survey is intended primarily for two readerships: general topologists who know a little model theory, and model theorists who know a little general topology. Both camps can boast a healthy constituency, and most of this paper should be readily accessible to anyone in either. The ultraproduct construction has a long and distinguished history. While its beginnings go back to the 1930s with K...
متن کاملGeneralized Ultraproduct and Kirman-Sondermann Correspondence for Vote Abstention
The present paper refines Herzberg and Eckert’s model-theoretic approach to aggregation. The proposed refinement is aimed at naturally accounting for vote abstention, and is technically based on a more general notion of ultraproduct than the one standardly occurring in model theory textbooks. Unlike the standard ultraproduct construction, which yields the empty model as soon as any one single c...
متن کاملFree independence in ultraproduct von Neumann algebras and applications
The main result of this paper is a generalization of Popa’s free independence result for subalgebras of ultraproduct II1 factors [Po95b] to the framework of ultraproduct von Neumann algebras (M, φ) where (M,φ) is a σ-finite von Neumann algebra endowed with a faithful normal state satisfying (M) ∩ M = C1. More precisely, we show that whenever P1, P2 ⊂ M ω are von Neumann subalgebras with separab...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Proceedings of the American Mathematical Society
سال: 1980
ISSN: 0002-9939
DOI: 10.1090/s0002-9939-1980-0572318-0