{"title":"Logics of upsets of De Morgan lattices","authors":"Adam Přenosil","doi":"10.1002/malq.202100076","DOIUrl":"10.1002/malq.202100076","url":null,"abstract":"<p>We study logics determined by matrices consisting of a De Morgan lattice with an upward closed set of designated values, such as the logic of non-falsity preservation in a given finite Boolean algebra and Shramko's logic of non-falsity preservation in the four-element subdirectly irreducible De Morgan lattice. The key tool in the study of these logics is the lattice-theoretic notion of an <i>n</i>-filter. We study the logics of all (complete, consistent, and classical) <i>n</i>-filters on De Morgan lattices, which are non-adjunctive generalizations of the four-valued logic of Belnap and Dunn (of the three-valued logics of Priest and Kleene, and of classical logic). We then show how to find a finite Hilbert-style axiomatization of any logic determined by a finite family of prime upsets of finite De Morgan lattices and a finite Gentzen-style axiomatization of any logic determined by a finite family of filters on finite De Morgan lattices. As an application, we axiomatize Shramko's logic of anything but falsehood.</p>","PeriodicalId":49864,"journal":{"name":"Mathematical Logic Quarterly","volume":"69 4","pages":"419-445"},"PeriodicalIF":0.3,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86044937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Spherically complete models of Hensel minimal valued fields","authors":"David B. Bradley-Williams, Immanuel Halupczok","doi":"10.1002/malq.202100055","DOIUrl":"https://doi.org/10.1002/malq.202100055","url":null,"abstract":"<p>We prove that Hensel minimal expansions of finitely ramified Henselian valued fields admit spherically complete immediate elementary extensions. More precisely, the version of Hensel minimality we use is 0-h<sup>mix</sup>-minimality (which, in equi-characteristic 0, amounts to 0-h-minimality).</p>","PeriodicalId":49864,"journal":{"name":"Mathematical Logic Quarterly","volume":"69 2","pages":"138-146"},"PeriodicalIF":0.3,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/malq.202100055","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50124173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Coding of real-valued continuous functions under \u0000 \u0000 WKL\u0000 $mathsf {WKL}$","authors":"Tatsuji Kawai","doi":"10.1002/malq.202200031","DOIUrl":"https://doi.org/10.1002/malq.202200031","url":null,"abstract":"<p>In the context of constructive reverse mathematics, we show that weak Kőnig's lemma (<math>\u0000 <semantics>\u0000 <mi>WKL</mi>\u0000 <annotation>$mathsf {WKL}$</annotation>\u0000 </semantics></math>) implies that every pointwise continuous function <math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>f</mi>\u0000 <mo>:</mo>\u0000 <mo>[</mo>\u0000 <mn>0</mn>\u0000 <mo>,</mo>\u0000 <mn>1</mn>\u0000 <mo>]</mo>\u0000 <mo>→</mo>\u0000 <mi>R</mi>\u0000 </mrow>\u0000 <annotation>$f : [0,1]rightarrow mathbb {R}$</annotation>\u0000 </semantics></math> is induced by a code in the sense of reverse mathematics. This, combined with the fact that <math>\u0000 <semantics>\u0000 <mi>WKL</mi>\u0000 <annotation>$mathsf {WKL}$</annotation>\u0000 </semantics></math> implies the Fan theorem, shows that <math>\u0000 <semantics>\u0000 <mi>WKL</mi>\u0000 <annotation>$mathsf {WKL}$</annotation>\u0000 </semantics></math> implies the uniform continuity theorem: every pointwise continuous function <math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>f</mi>\u0000 <mo>:</mo>\u0000 <mo>[</mo>\u0000 <mn>0</mn>\u0000 <mo>,</mo>\u0000 <mn>1</mn>\u0000 <mo>]</mo>\u0000 <mo>→</mo>\u0000 <mi>R</mi>\u0000 </mrow>\u0000 <annotation>$f : [0,1]rightarrow mathbb {R}$</annotation>\u0000 </semantics></math> has a modulus of uniform continuity. Our results are obtained in Heyting arithmetic in all finite types with quantifier-free axiom of choice.</p>","PeriodicalId":49864,"journal":{"name":"Mathematical Logic Quarterly","volume":"69 3","pages":"370-391"},"PeriodicalIF":0.3,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50142952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}