{"id":4709,"date":"2022-05-06T11:24:39","date_gmt":"2022-05-06T09:24:39","guid":{"rendered":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/?p=4709"},"modified":"2022-06-09T18:44:04","modified_gmt":"2022-06-09T16:44:04","slug":"lira-session-krisztina-fruzsa","status":"publish","type":"post","link":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/2022\/05\/lira-session-krisztina-fruzsa\/","title":{"rendered":"LIRa session: Krisztina Fruzsa"},"content":{"rendered":"<p>Speaker: <a href=\"https:\/\/logic-cs.at\/phd\/students\/krisztina-fruzsa\/\">Krisztina Fruzsa<\/a> (TU Wien)<\/p>\n<p>Date and Time: Thursday, June&nbsp;9th 2022, 16:30-18:00, Amsterdam time.<\/p>\n<p>Venue: online. <a href=\"https:\/\/video.uva.nl\/media\/LIRa+seminar+on+2022-06-09+by+Krisztina+Fruzsa\/0_09u61oro\">recording available, click here<\/a><\/p>\n<p>Title: <strong>New hope for epistemic reasoning in byzantine fault-tolerant distributed systems.<\/strong><\/p>\n<p>Abstract. The epistemic approach to the study of various models of distributed systems has shown to be fruitful over the last three decades. In this talk, I will present some of the results in the area w.r.t. the byzantine fault-tolerant model. By extending Fagin et al.\u2019s classic runs-and-systems framework, we have developed a comprehensive framework that also allows modelling misbehaviours of byzantine agents. In this extended framework, we prove the so-called Brain-in-a-Vat Lemma (formalizing the brain-in-a-vat scenario), one of our central results. In this talk we will take a closer look at this result to see how using its various knowledge limitations can be represented in the logical language. We will also take a look at some of our most recent results on the topic, one of them being an alternative axiomatization of the so-called hope modality that has been introduced in the context of epistemic analysis of byzantine fault-tolerant systems. We will see that, essentially, hope can be described using a standard KB4_n system. We will also see how we can combine KB4_n hope modalities with S5_n knowledge modalities in a joint logic enriched with both common hope and common knowledge. Interestingly, in the corresponding logics some of the main properties of the above-mentioned systems such as the bound on the maximal number of byzantine faulty agents and the brain-in-a-vat related properties become frame-characterizable.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Speaker: Krisztina Fruzsa (TU Wien)<br \/>\nDate and Time: Thursday, June&nbsp;9th 2022, 16:30-18:00, Amsterdam time.<br \/>\nVenue: online. recording available, click here<br \/>\nTitle: New hope for epistemic reasoning in byzantine fault-tolerant distributed systems.<br \/>\nAbstract. The epistemic approach to the study of various models of distributed systems has shown to be fruitful over the last three decades. In this talk, I will [&#8230;]<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-4709","post","type-post","status-publish","format-standard","hentry","category-events"],"_links":{"self":[{"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/posts\/4709","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/comments?post=4709"}],"version-history":[{"count":4,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/posts\/4709\/revisions"}],"predecessor-version":[{"id":4739,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/posts\/4709\/revisions\/4739"}],"wp:attachment":[{"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/media?parent=4709"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/categories?post=4709"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/tags?post=4709"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}