Document Type
Article
Language
eng
Format of Original
16 p.
Publication Date
1-2006
Publisher
Springer
Source Publication
Archive for Mathematical Logic
Source ISSN
0933-5846
Original Item ID
doi: 10.1007/s00153-004-0238-y
Abstract
The Chang-Łoś-Suszko theorem of first-order model theory characterizes universal-existential classes of models as just those elementary classes that are closed under unions of chains. This theorem can then be used to equate two model-theoretic closure conditions for elementary classes; namely unions of chains and existential substructures. In the present paper we prove a topological analogue and indicate some applications.
COinS
Comments
Accepted version. Archive for Mathematical Logic, Vol. 45, No. 1 (January, 2006): 97-112. DOI. © 2006 Springer. Used with permission.