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<p>Hi everyone,</p>
<p>this is a brief reminder for the talk by <b>Andreas Herzig </b>in
our next NMR Online Seminar <b>today at 16:00</b>. </p>
<p>See you there!</p>
<p><br>
</p>
<div class="moz-cite-prefix">Am 07.12.25 um 17:11 schrieb Jonas
Haldimann:<br>
</div>
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<h3>NMR Online Seminar</h3>
<p><br>
<font face="monospace"><font size="4">-- Summary:
------------------------------------------------------------------<br>
<br>
What? Next talk in the NMR online talk series by
Andreas Herzig<br>
When? Wednesday, 10. December 2025, 16:00 CET
(UCT+1)<br>
Where? Online (Zoom): <a
class="moz-txt-link-freetext"
href="https://uct-za.zoom.us/j/92600685092?pwd=ErqWWWKrljbjxLi0CNsgEZr4WR7ZHN.1"
moz-do-not-send="true">https://uct-za.zoom.us/j/92600685092?pwd=ErqWWWKrljbjxLi0CNsgEZr4WR7ZHN.1</a><br>
<br>
<a class="moz-txt-link-freetext"
href="https://nmrseminar.krportal.org/"
moz-do-not-send="true">https://nmrseminar.krportal.org/</a><br>
------------------------------------------------------------------------------</font><br>
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We are happy to announce that the NMR online talk series
restarts after the summer break with a talk given by<br>
<b>Andreas Herzig</b> (IRIT)<br>
on <b>Wednesday, 10. December 2025</b>, 16:00 CET:</p>
<p><span><span style="font-weight: bold;">Relevance and
irrelevance in classical and modal revision</span></span></p>
<div class="fs-6 collapse show"
id="divAbstractMartinezOctober2025"> </div>
<p><font size="2"><i>Abstract.</i> Two different notions of
irrelevance have been much debated in the belief
revision literature: irrelevance of syntax and
irrelevance of a piece of information. The former is a
basic postulate of the AGM framework but has been
criticised as being too strong. The latter may be
violated by AGM revision operations, and Parikh
(followed by, among others, Makinson and Peppas) has
argued that such a postulate should be added to the AGM
framework. My talk will re-examine several aspects of
irrelevance. First, I will argue that if one takes the
arguments for syntax relevance seriously then an
operation of reformulation of belief bases should be
added to the picture. Second, I will argue for syntax
irrelevance by showing that the most striking
counter-examples can be accommodated if classical
material implication is replaced by strict implication.
Third, I will show that this leads to an account of
revision operations for modal logics. Fourth, I will
weaken Parikh's relevance postulate to an intuitively
appealing postulate of vocabulary preservation that may
also be violated by AGM revision operations. Fifth, I
will define a modal revision operation satisfying AGM,
vocabulary preservation, and relevance.<br>
The talk is based on two papers that were presented at
AAAI 2025: "On the Logic of Theory Base Change:
Reformulation of Belief Bases" (with E.L. Fermé and M.V.
Martinez) and "Minimal Change in Modal Logic S5" (with
C. Aguilera-Ventura and J. Ben-Naim), as well as ongoing
work. </font></p>
<div class="fs-6 collapse show"
id="divAbstractHerzigDecember2025"> </div>
<p>The talk will be given via Zoom.</p>
<p>The plan of this series to have a talk roughly once per
month. If you are interested in learning the next
speakers, please visit the website at<br>
<a class="moz-txt-link-freetext"
href="https://nmrseminar.krportal.org/"
moz-do-not-send="true">https://nmrseminar.krportal.org/</a></p>
<p>We are still looking for speakers for future talks. If
there is something you would like to present in this
seminar series, please do not hesitate to contact us.</p>
Kind regards,<br>
Jonas and Giovanni<br>
<br>
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