{"id":5542,"date":"2026-01-09T11:01:38","date_gmt":"2026-01-09T10:01:38","guid":{"rendered":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/?p=5542"},"modified":"2026-03-31T11:50:43","modified_gmt":"2026-03-31T09:50:43","slug":"lira-session-malvin-gattinger-2","status":"publish","type":"post","link":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/2026\/01\/lira-session-malvin-gattinger-2\/","title":{"rendered":"LIRa session: Malvin Gattinger"},"content":{"rendered":"<p>Speaker: <a href=\"https:\/\/malv.in\/\">Malvin Gattinger<\/a> (ILLC, University of Amsterdam)<\/p>\n<p>Date and Time: Thursday, April&nbsp;9th 2026, 15:30-17:00<br \/>\n(Please note the earlier-than-usual time.)<\/p>\n<p>Venue: ILLC Seminar Room F1.15, Science Park 107 <strong>and<\/strong>\u00a0<a href=\"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/guidelines-for-online-sessions\/\">online<\/a>.<\/p>\n<p>Title: <strong>Do you know if the road is still there? Sabotage Modal Logic with Knowledge.<\/strong><\/p>\n<p><em>Abstract. <\/em>Sabotage Modal Logic (SML), originally proposed by Johan van Benthem, is concerned with a two-player game between traveller and demon played on a graph: traveller wants to get from A to B, but demon may delete edges between nodes. Formally, the traveller is modelled by a standard diamond modality whereas the demon is a dynamic modality that deletes edges. Different versions of the resulting logic have been studied in the literature.<\/p>\n<p>In this talk I will describe ongoing work where we add a third modality: the knowledge of the traveller. The resulting language we call SML+K and it can express sentences such as &#8220;After any two deletions the traveller still knows that there is a three-step path to the goal&#8221;. Or &#8220;There is a deletion after which there still is a three-step path to the goal but the traveller will no longer know that there is such a path.&#8221;<\/p>\n<p>We developed two semantics for SML+K, one where the knowledge is encoded by an equivalence relation between histories and one where the traveller only stores a set of graphs currently considered possible. At first sight only one of these semantics seems to have perfect-recall, but we actually aim to show that they are equivalent.<\/p>\n<p>For both semantics I will also present a Lean formalization that can also be used as a model checker.<\/p>\n<p>This is joint work with Sujata Ghosh and Saptarshi Sahoo (both Chennai).<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Speaker: Malvin Gattinger (ILLC, University of Amsterdam)<br \/>\nDate and Time: Thursday, April&nbsp;9th 2026, 15:30-17:00<br \/>\n(Please note the earlier-than-usual time.)<br \/>\nVenue: ILLC Seminar Room F1.15, Science Park 107 and\u00a0online.<br \/>\nTitle: Do you know if the road is still there? Sabotage Modal Logic with Knowledge.<br \/>\nAbstract. Sabotage Modal Logic (SML), originally proposed by Johan van Benthem, is concerned with a two-player game [&#8230;]<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[14],"tags":[],"class_list":["post-5542","post","type-post","status-publish","format-standard","hentry","category-all"],"_links":{"self":[{"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/posts\/5542","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=5542"}],"version-history":[{"count":3,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/posts\/5542\/revisions"}],"predecessor-version":[{"id":5606,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/posts\/5542\/revisions\/5606"}],"wp:attachment":[{"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/media?parent=5542"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/categories?post=5542"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/tags?post=5542"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}