{"title":"Commutative unital rings elementarily equivalent to prescribed product rings","authors":"P. D'Aquino, A. Macintyre","doi":"10.4064/fm232-8-2023","DOIUrl":"https://doi.org/10.4064/fm232-8-2023","url":null,"abstract":"The classical work of Feferman Vaught gives a powerful, constructive analysis of definability in (generalized) product structures, and certain associated enriched Boolean structures. %structures in terms of definability in the component structures. Here, by closely related methods, but in the special setting of commutative unital rings, we obtain a kind of converse allowing us to determine in interesting cases, when a commutative unital R is elementarily equivalent to a nontrivial product of a family of commutative unital rings R_i. We use this in the model theoretic analysis of residue rings of models of Peano Arithmetic.","PeriodicalId":55138,"journal":{"name":"Fundamenta Mathematicae","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139357538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Consequences of Vopěnka’s Principle over weak set theories","authors":"A. Tzouvaras","doi":"10.4064/fm982-1-2016","DOIUrl":"https://doi.org/10.4064/fm982-1-2016","url":null,"abstract":"It is shown that Vopv{e}nka's Principle (VP) can restore almost the entire ZF over a weak fragment of it. Namely, if EST is the theory consisting of the axioms of Extensionality, Empty Set, Pairing, Union, Cartesian Product, $Delta_0$-Separation and Induction along $omega$, then ${rm EST+VP}$ proves the axioms of Infinity, Replacement (thus also Separation) and Powerset. The result was motivated by previous results in cite{Tz14}, as well as by H. Friedman's cite{Fr05}, where a distinction is made among various forms of VP. As a corollary, ${rm EST}+$Foundation$+{rm VP}$=${rm ZF+VP}$, and ${rm EST}+$Foundation$+{rm AC+VP}={rm ZFC+VP}$. Also it is shown that the Foundation axiom is independent from ZF--{Foundation}+${rm VP}$. It is open whether the Axiom of Choice is independent from ${rm ZF+VP}$. A very weak form of choice follows from VP and some similar other forms of choice are introduced.","PeriodicalId":55138,"journal":{"name":"Fundamenta Mathematicae","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45923563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A bounded sequence of bitransitive and capture Sierpiński curve Julia sets for 3-circle inversions","authors":"Daniel M. Look","doi":"10.4064/fm166-4-2023","DOIUrl":"https://doi.org/10.4064/fm166-4-2023","url":null,"abstract":"","PeriodicalId":55138,"journal":{"name":"Fundamenta Mathematicae","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70215788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On recurrence and entropy in the hyperspace of continua in dimension one","authors":"Domagoj Jelić, Piotr Oprocha","doi":"10.4064/fm235-4-2023","DOIUrl":"https://doi.org/10.4064/fm235-4-2023","url":null,"abstract":"We show that if $G$ is a topological graph, and $fcolon Gto G$ is a continuous map, then the induced map $tilde {f}$ defined on the hyperspace $C(G)$ of all connected subsets of $G$ by the natural formula $tilde {f}(C)=f(C)$ carries the same entro","PeriodicalId":55138,"journal":{"name":"Fundamenta Mathematicae","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135056928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ramification current, post-critical normality and stability of holomorphic endomorphisms of $mathbb P^k$","authors":"François Berteloot, Maxence Brévard","doi":"10.4064/fm279-6-2023","DOIUrl":"https://doi.org/10.4064/fm279-6-2023","url":null,"abstract":"In the context of holomorphic families of endomorphisms of $mathbb P^k$, we prove that stability in the sense of [F. Berteloot et al., Ann. Sci. École Norm. Sup. 51 (2018)] is equivalent to a summability condition for the post-critical mass and to the co","PeriodicalId":55138,"journal":{"name":"Fundamenta Mathematicae","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135957904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dimension of images and graphs of little Lipschitz functions","authors":"","doi":"10.4064/fm147-12-2022","DOIUrl":"https://doi.org/10.4064/fm147-12-2022","url":null,"abstract":"","PeriodicalId":55138,"journal":{"name":"Fundamenta Mathematicae","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70203168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The complexity of homeomorphism relations on some classes of compacta with bounded topological dimension","authors":"Jan Dudák, Benjamin Vejnar","doi":"10.4064/fm164-8-2023","DOIUrl":"https://doi.org/10.4064/fm164-8-2023","url":null,"abstract":"We are dealing with the complexity of the homeomorphism relation on some classes of metrizable compacta from the viewpoint of invariant descriptive set theory. We prove that the homeomorphism relation for absolute retracts in the plane is Borel bireducibl","PeriodicalId":55138,"journal":{"name":"Fundamenta Mathematicae","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135784457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}