N. M. Mussina, I. O. Tungushbayeva, A. R. Yeshkeyev
{"title":"Conditions for Existence of Jonsson Hybrids","authors":"N. M. Mussina, I. O. Tungushbayeva, A. R. Yeshkeyev","doi":"10.1007/s10469-026-09839-z","DOIUrl":null,"url":null,"abstract":"<p>We investigate the existence of hybrids of Jonsson theories in various first-order languages. A general framework for hybrids is constructed, defined by ∀∃-sentences true in the Cartesian product of semantic models. For theories in the same language, examples of hybrids are provided; necessary and sufficient conditions for the existence of a hybrid in a functional signature are established; it is shown that a hybrid can inherit properties of the original theories (perfection, categoricity, stability). For theories in different languages, the existence of hybrids is proved for arbitrary enrichments of semantic models to the joint language, and an amalgam is constructed. It is shown that hybrids can differ depending on the enrichments.</p>","PeriodicalId":7422,"journal":{"name":"Algebra and Logic","volume":"64 5","pages":"349 - 369"},"PeriodicalIF":0.4000,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Algebra and Logic","FirstCategoryId":"100","ListUrlMain":"https://link.springer.com/article/10.1007/s10469-026-09839-z","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"LOGIC","Score":null,"Total":0}
引用次数: 0
Abstract
We investigate the existence of hybrids of Jonsson theories in various first-order languages. A general framework for hybrids is constructed, defined by ∀∃-sentences true in the Cartesian product of semantic models. For theories in the same language, examples of hybrids are provided; necessary and sufficient conditions for the existence of a hybrid in a functional signature are established; it is shown that a hybrid can inherit properties of the original theories (perfection, categoricity, stability). For theories in different languages, the existence of hybrids is proved for arbitrary enrichments of semantic models to the joint language, and an amalgam is constructed. It is shown that hybrids can differ depending on the enrichments.
期刊介绍:
This bimonthly journal publishes results of the latest research in the areas of modern general algebra and of logic considered primarily from an algebraic viewpoint. The algebraic papers, constituting the major part of the contents, are concerned with studies in such fields as ordered, almost torsion-free, nilpotent, and metabelian groups; isomorphism rings; Lie algebras; Frattini subgroups; and clusters of algebras. In the area of logic, the periodical covers such topics as hierarchical sets, logical automata, and recursive functions.
Algebra and Logic is a translation of ALGEBRA I LOGIKA, a publication of the Siberian Fund for Algebra and Logic and the Institute of Mathematics of the Siberian Branch of the Russian Academy of Sciences.
All articles are peer-reviewed.