{"id":613,"date":"2010-03-31T18:36:03","date_gmt":"2010-03-31T18:36:03","guid":{"rendered":"http:\/\/www.illc.uva.nl\/lgc\/seminar\/?p=613"},"modified":"2010-04-18T09:55:32","modified_gmt":"2010-04-18T09:55:32","slug":"seminar-session-on-april-12","status":"publish","type":"post","link":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/2010\/03\/seminar-session-on-april-12\/","title":{"rendered":"Seminar Session on April 12"},"content":{"rendered":"

Monday April 12<\/strong> we will have another session of our seminar. Dick de Jongh<\/strong> and Lorenz Demey<\/strong> will present their work according to the program below. The session will start at 14:00 hrs<\/strong>, and will take place in Bushuis F0.22<\/a>.<\/strong><\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
<\/td>\n<\/tr>\n
14:00 – 14:40<\/td>\n<\/td>\nDick de Jongh
\n<\/strong><\/td>\n<\/tr>\n
<\/td>\n<\/td>\n (ILLC<\/em>)<\/em><\/td>\n<\/tr>\n
<\/td>\n<\/td>\nComparing Strenghts of Beliefs explicitly<\/a><\/td>\n<\/tr>\n
\n
\n
Inspired by a similar use in provability logic, formulas p<\/em> > q<\/em><\/div>\n
and p<\/em> \u2265 q<\/em> are introduced in the existing logical framework for<\/div>\n
discussing beliefs to express that the strength of belief in p is<\/div>\n
greater than (or equal to) that in q. This explicit mention of the<\/div>\n
comparison in the logical language enables one to apply the system<\/div>\n
to situations which are outside of the range of standard doxastic logic.<\/div>\n
Moreover it enables one to formalize the intuitive idea that one wants<\/div>\n
to consider only those situations which one considers to be possible<\/div>\n
(one believes in the occurrence of such situations more than in the<\/div>\n
contradiction), and which are the ones that inhabit the usual models<\/div>\n
of logics of knowledge and belief. It also\u00a0aids in defining several less<\/div>\n
common\u00a0concepts in a uniform way, notions like plausibility (in the<\/div>\n
sense of `more plausible than not’) and disbelief. Finally, it<\/div>\n
assists in studying the properties of the concept of greater<\/div>\n
strength of belief itself.<\/div>\n
Our basic semantics uses an ordering of the sets of worlds (propositions)<\/div>\n
of the model.\u00a0A heavy part is played in our\u00a0investigations by the<\/div>\n
relationship between \u00a0the standard plausibility\u00a0ordering of the worlds and<\/div>\n
our strength of belief\u00a0ordering of the propositions. We discuss\u00a0the<\/div>\n
possibility of defining the\u00a0one in terms of the other. The few words\u00a0which<\/div>\n
time will allow us by then\u00a0will be devoted\u00a0to dynamics – the\u00a0change of the<\/div>\n
ordering under the\u00a0influence of hard and soft information.<\/div>\n
The work is in cooperation with Sujata Ghosh.<\/div>\n<\/blockquote>\n<\/td>\n<\/tr>\n
<\/td>\n<\/tr>\n
14:40 – 14:50<\/td>\n<\/td>\nQuestions and Discussion<\/td>\n<\/tr>\n
14:50 – 15:00<\/td>\n<\/td>\nCoffee break<\/td>\n<\/tr>\n
\n
\n<\/td>\n<\/tr>\n
15:00 – 15:40<\/td>\n<\/td>\nLorenz Demey<\/strong><\/td>\n<\/tr>\n
<\/td>\n<\/td>\n (ILLC and University of Leuven) <\/em><\/td>\n<\/tr>\n
<\/td>\n<\/td>\nAgreeing to Disagree in Probabilistic DEL<\/a><\/td>\n<\/tr>\n
\n

Aumann proved in 1976 that if two agents with common priors have common
\nknowledge about their posteriors, then these posteriors must coincide.
\nRecently, Roy and D\u00e9gremont have formalized a qualitative version of this
\ntheorem in the setting of epistemic plausibility models. In this talk, we
\nwill formalize it in the setting of probabilistic Kripke models.<\/p>\n

On the technical level, the (semantic) proof of the agreement theorem
\nturns out to be a straightforward adaptation of Aumann’s original proof,
\nthus establishing probabilistic Kripke models as a natural setting in
\nwhich to explore these issues. Furthermore, we will provide
\ncharacterization results for all of the assumptions needed in the theorem,
\nand look for a complete axiomatization that captures our semantic
\nreasoning.<\/p>\n

On a more methodological level, we will emphasize the dynamics part as an
\nessential component of the agreement theorem, and even argue that Aumann’s
\noriginal theorem is static only because of his convoluted notion of model.
\nFrom this perspective, our work is a new illustration of van Benthem’s
\nclaim that many classical static results are actually based on intuitions
\ninvolving a large dynamic component, and that these dynamic components can
\n(and should) be made explicit.<\/p><\/blockquote>\n<\/td>\n<\/tr>\n

<\/td>\n<\/tr>\n
15:50 – 15:50<\/td>\n<\/td>\nQuestions and Discussion<\/td>\n<\/tr>\n
<\/td>\n<\/tr>\n
15:50 – 16:00<\/td>\n<\/td>\nGeneral Discussion<\/td>\n<\/tr>\n
\n
\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
Three challenges for a logical theory of intentions<\/div>\n","protected":false},"excerpt":{"rendered":"

Monday April 12 we will have another session of our seminar. Dick de Jongh and Lorenz Demey will present their work according to the program below. The session will start at 14:00 hrs, and will take place in Bushuis F0.22.<\/p>\n

14:00 – 14:40<\/p>\n

Dick de Jongh<\/p>\n

(ILLC)<\/p>\n

Comparing Strenghts of Beliefs explicitly<\/p>\n

Inspired by a similar use in […]<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-613","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\/613","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=613"}],"version-history":[{"count":10,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/posts\/613\/revisions"}],"predecessor-version":[{"id":619,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/posts\/613\/revisions\/619"}],"wp:attachment":[{"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/media?parent=613"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/categories?post=613"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/projects.illc.uva.nl\/lgc\/seminar\/wp-json\/wp\/v2\/tags?post=613"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}