{"id":1111,"date":"2022-11-29T09:38:57","date_gmt":"2022-11-29T08:38:57","guid":{"rendered":"https:\/\/dottorati.unica.it\/matematicaeinformatica\/?p=1111"},"modified":"2023-12-11T20:20:13","modified_gmt":"2023-12-11T19:20:13","slug":"seminario-dottorale-factorizations-in-monoids-and-rings-laura-cossu-university-of-graz","status":"publish","type":"post","link":"https:\/\/dottorati.unica.it\/matematicaeinformatica\/2022\/11\/29\/seminario-dottorale-factorizations-in-monoids-and-rings-laura-cossu-university-of-graz\/","title":{"rendered":"PhD Course: Factorizations in monoids and rings"},"content":{"rendered":"<h1>Factorizations in monoids and rings<\/h1>\n<p><strong>Laura Cossu<\/strong><br \/>\nUniversity of Graz<\/p>\n<p><strong>Outline<\/strong><\/p>\n<p><span dir=\"ltr\" role=\"presentation\">Many problems in algebra involve the decomposition of certain elements of a ring (or more generally <\/span><span dir=\"ltr\" role=\"presentation\">of a monoid) into a product of certain other elements (hereinafter generically referred to as building <\/span><span dir=\"ltr\" role=\"presentation\">blocks) that are in some sense minimal. The classical theory of factorization investigates factorizations <\/span><span dir=\"ltr\" role=\"presentation\">in which the building blocks are atoms, i.e., non-unit elements of a monoid that are not products of <\/span><span dir=\"ltr\" role=\"presentation\">two non-units. For example, it is well known that every non-zero non-unit of a Dedekind domain (more <\/span><span dir=\"ltr\" role=\"presentation\">generally, of a Noetherian domain) can be written as a finite product of atoms and that in general <\/span><span dir=\"ltr\" role=\"presentation\">such decompositions are not unique. On the other hand, examples of factorizations that lie beyond the <\/span><span dir=\"ltr\" role=\"presentation\">scope of the classical theory include additive decompositions into multiplicative units in rings; cyclic <\/span><span dir=\"ltr\" role=\"presentation\">decompositions of permutations in the symmetric group of degree n; idempotent factorizations of the <\/span><span dir=\"ltr\" role=\"presentation\">\u201csingular elements\u201d of a monoid; and so on.<\/span><\/p>\n<p><span dir=\"ltr\" role=\"presentation\">After an introductory overview of the history and main results in the classical framework, in this <\/span><span dir=\"ltr\" role=\"presentation\">course, we combine the language of monoids and preorders (partial orders that are not necessarily an<\/span><span dir=\"ltr\" role=\"presentation\">tisymmetric) to make first steps towards the construction of a \u201cunified theory of factorization\u201d.<\/span> <span dir=\"ltr\" role=\"presentation\">In <\/span><span dir=\"ltr\" role=\"presentation\">particular, we prove an abstract existence theorem that recover, among others, a classical theorem of <\/span><span dir=\"ltr\" role=\"presentation\">Cohn on atomic factorizations in cancellative monoids, a classical result by Anderson and Valdes-Leon <\/span><span dir=\"ltr\" role=\"presentation\">on \u201cirreducible factorizations\u201d in commutative monoids, but also a theorem by Erdos on idempotent fac<\/span><span dir=\"ltr\" role=\"presentation\">torizations of square singular matrices over fields. We also introduce a notion of \u201cminimal factorization\u201d, <\/span><span dir=\"ltr\" role=\"presentation\">suitable for the new abstract setting, and we qualify and quantify the related non-uniqueness properties <\/span><span dir=\"ltr\" role=\"presentation\">in specific cases but also in some generality. Examples will help to motivate and illustrate the theory. <\/span><\/p>\n<p><span dir=\"ltr\" role=\"presentation\">Prerequisites:<\/span> <span dir=\"ltr\" role=\"presentation\">Standard knowledge of (basic) algebraic structures and (binary) relations.<\/span><\/p>\n<p><span dir=\"ltr\" role=\"presentation\">Duration of the course:<\/span> <span dir=\"ltr\" role=\"presentation\">10 hours.<\/span><\/p>\n<p><strong>Schedule<\/strong><\/p>\n<p>&#8211; November 28, 16:00-18:00 (Aula B)<br \/>\n&#8211; November 29, 16:00-18:00 (Aula A)<br \/>\n&#8211; November 30, 16:00-18:00 (Aula A)<br \/>\n&#8211; December 1, 16:00-18:00 (Aula A)<br \/>\n&#8211; December 2, 16:00-18:00 (Aula A)<\/p>\n<p><span dir=\"ltr\" role=\"presentation\"><strong>Exam<\/strong><\/span><\/p>\n<p><span dir=\"ltr\" role=\"presentation\">Written. Writing of a short essay.<\/span><\/p>\n<p><strong><span dir=\"ltr\" role=\"presentation\">References<\/span><\/strong><\/p>\n<p><span dir=\"ltr\" role=\"presentation\">1. L. Cossu and S. Tringali,<\/span> <strong><span dir=\"ltr\" role=\"presentation\">Abstract Factorization Theorems with Applications to Idempotent Factor<\/span><span dir=\"ltr\" role=\"presentation\">izations<\/span><\/strong><span dir=\"ltr\" role=\"presentation\">, e-print (Aug. 2021),<\/span> <span dir=\"ltr\" role=\"presentation\">arXiv:2108.12379<\/span><span dir=\"ltr\" role=\"presentation\">.<\/span><br role=\"presentation\" \/><span dir=\"ltr\" role=\"presentation\">2. L. Cossu and S. Tringali,<\/span> <strong><span dir=\"ltr\" role=\"presentation\">Factorization under Local Finiteness Conditions<\/span><\/strong><span dir=\"ltr\">, e-print (Aug. 2022), <\/span><span dir=\"ltr\" role=\"presentation\">arXiv:2208.05869<\/span><span dir=\"ltr\" role=\"presentation\">.<\/span><br role=\"presentation\" \/><span dir=\"ltr\" role=\"presentation\">3. A. Geroldinger and F. Halter-Koch,<\/span> <span dir=\"ltr\" role=\"presentation\"><strong>Non-Unique Factorizations<\/strong>. Algebraic, Combinatorial and An<\/span><span dir=\"ltr\" role=\"presentation\">alytic Theory<\/span><span dir=\"ltr\" role=\"presentation\">, Pure Appl. Math.<\/span> <span dir=\"ltr\" role=\"presentation\">278<\/span><span dir=\"ltr\" role=\"presentation\">, Chapman &amp; Hall\/CRC, Boca Raton (FL), 2006.<\/span><br role=\"presentation\" \/><span dir=\"ltr\" role=\"presentation\">4. S. Tringali,<\/span> <strong><span dir=\"ltr\" role=\"presentation\">An Abstract Factorization Theorem and Some Applications<\/span><\/strong><span dir=\"ltr\" role=\"presentation\">, J. Algebra 602 (2022), 352\u2013<\/span><span dir=\"ltr\" role=\"presentation\">380.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Factorizations in monoids and rings Laura Cossu University of Graz Outline Many problems in algebra involve the decomposition of certain elements of a ring (or more generally of a monoid) into a product of certain other [&hellip;]<\/p>\n","protected":false},"author":3006,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-1111","post","type-post","status-publish","format-standard","hentry","category-news"],"_links":{"self":[{"href":"https:\/\/dottorati.unica.it\/matematicaeinformatica\/wp-json\/wp\/v2\/posts\/1111","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dottorati.unica.it\/matematicaeinformatica\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dottorati.unica.it\/matematicaeinformatica\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dottorati.unica.it\/matematicaeinformatica\/wp-json\/wp\/v2\/users\/3006"}],"replies":[{"embeddable":true,"href":"https:\/\/dottorati.unica.it\/matematicaeinformatica\/wp-json\/wp\/v2\/comments?post=1111"}],"version-history":[{"count":5,"href":"https:\/\/dottorati.unica.it\/matematicaeinformatica\/wp-json\/wp\/v2\/posts\/1111\/revisions"}],"predecessor-version":[{"id":1265,"href":"https:\/\/dottorati.unica.it\/matematicaeinformatica\/wp-json\/wp\/v2\/posts\/1111\/revisions\/1265"}],"wp:attachment":[{"href":"https:\/\/dottorati.unica.it\/matematicaeinformatica\/wp-json\/wp\/v2\/media?parent=1111"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dottorati.unica.it\/matematicaeinformatica\/wp-json\/wp\/v2\/categories?post=1111"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dottorati.unica.it\/matematicaeinformatica\/wp-json\/wp\/v2\/tags?post=1111"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}