<div dir="ltr">Dear all,<br><br>This coming Friday we have Ugo Dal Lago (Bologna) and<br>Paul-Andre Mellies (Paris VII) visiting us in U Tokyo and making<br>talks. Feel free to join us. See you there!<br><br>Best regards,<br>
Ichiro Hasuo<br><a href="http://www-mmm.is.s.u-tokyo.ac.jp/?plain=false&lang=en&pos=seminar">http://www-mmm.is.s.u-tokyo.ac.jp/?plain=false&lang=en&pos=seminar</a><span class=""></span><span class=""></span><br>
<br><hr><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:bold;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline"></span><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt">
<span style="font-size:19px;font-family:Arial;color:rgb(0,0,0);background-color:rgb(255,255,255);font-weight:bold;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">Fri 8 November 2013, 10:00-12:00</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><a href="http://www.pps.jussieu.fr/~mellies/" style="text-decoration:none"><span style="font-size:15px;font-family:Arial;color:rgb(17,85,204);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:underline;vertical-align:baseline">Paul-Andre Mellies</span></a><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline"> (U. Paris VII), </span><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:bold;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline"></span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:bold;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">What a geometry of reasoning would look like?</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:11px;font-family:Arial;color:rgb(0,0,0);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">$BM}3XIt(B7$B9f4[(B</span><span style="font-size:11px;font-family:Arial;color:rgb(255,0,0);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">$BCO2<(B 007$B65<<(B Room 007 (underground floor)</span><span style="font-size:11px;font-family:Arial;color:rgb(0,0,0);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">, School of Science Bldg. No. 7</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:11px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">$B%"%/%;%9!'(B</span><a href="https://www-mmm.is.s.u-tokyo.ac.jp/indexj.html" style="text-decoration:none"><span style="font-size:11px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline"> </span><span style="font-size:11px;font-family:Arial;color:rgb(17,85,204);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:underline;vertical-align:baseline">https://www-mmm.is.s.u-tokyo.ac.jp/indexj.html</span></a></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:11px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">Access:</span><a href="http://www-mmm.is.s.u-tokyo.ac.jp/" style="text-decoration:none"><span style="font-size:11px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline"> </span><span style="font-size:11px;font-family:Arial;color:rgb(17,85,204);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:underline;vertical-align:baseline">http://www-mmm.is.s.u-tokyo.ac.jp/</span></a></p>
<br><span style="font-size:12px;font-family:Arial;color:rgb(102,102,102);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline"></span><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt">
<span style="font-size:12px;font-family:Arial;color:rgb(102,102,102);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">If one proceeds by analogy with mathematical physics, it is natural to inquire</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:12px;font-family:Arial;color:rgb(102,102,102);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">the geometric (rather than simply symbolic) nature of logical reasoning.</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:12px;font-family:Arial;color:rgb(102,102,102);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">In this introductory talk, I will describe how this question may be investigated</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:12px;font-family:Arial;color:rgb(102,102,102);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">starting from a series of recent advances at the converging point of proof theory</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:12px;font-family:Arial;color:rgb(102,102,102);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">and of programming language semantics. In particular, I will explain how</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:12px;font-family:Arial;color:rgb(102,102,102);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">a careful study of linear continuations, the most elementary mechanism</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:12px;font-family:Arial;color:rgb(102,102,102);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">common to proofs and to programs, enables one to evacuate the historical divide</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:12px;font-family:Arial;color:rgb(102,102,102);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">between classical and constructive logic, and reveals the existence</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:12px;font-family:Arial;color:rgb(102,102,102);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">of a logical pulsation which regulates reasoning and whose geometry</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:12px;font-family:Arial;color:rgb(102,102,102);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">is related to well-known structures in mathematical physics.</span></p>
<br><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:bold;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline"></span><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt">
<a href="http://www.cs.unibo.it/~dallago/" style="text-decoration:none"><span style="font-size:15px;font-family:Arial;color:rgb(17,85,204);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:underline;vertical-align:baseline">Ugo Dal Lago</span></a><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline"> (U. Bologna),<br class="">
</span><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:rgb(255,255,255);font-weight:bold;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">Applicative Bisimulation for Probabilistic Lambda-Calculus</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:11px;font-family:Arial;color:rgb(0,0,0);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">$BM}3XIt(B7$B9f4[(B</span><span style="font-size:11px;font-family:Arial;color:rgb(255,0,0);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">$BCO2<(B 007$B65<<(B Room 007 (underground floor)</span><span style="font-size:11px;font-family:Arial;color:rgb(0,0,0);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">, School of Science Bldg. No. 7</span></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:11px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">$B%"%/%;%9!'(B</span><a href="https://www-mmm.is.s.u-tokyo.ac.jp/indexj.html" style="text-decoration:none"><span style="font-size:11px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline"> </span><span style="font-size:11px;font-family:Arial;color:rgb(17,85,204);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:underline;vertical-align:baseline">https://www-mmm.is.s.u-tokyo.ac.jp/indexj.html</span></a></p>
<p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:11px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">Access:</span><a href="http://www-mmm.is.s.u-tokyo.ac.jp/" style="text-decoration:none"><span style="font-size:11px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline"> </span><span style="font-size:11px;font-family:Arial;color:rgb(17,85,204);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:underline;vertical-align:baseline">http://www-mmm.is.s.u-tokyo.ac.jp/</span></a></p>
<br><a href="http://www-mmm.is.s.u-tokyo.ac.jp/" style="text-decoration:none"><span style="font-size:11px;font-family:Arial;color:rgb(17,85,204);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:underline;vertical-align:baseline"></span></a><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt">
<span style="font-size:12px;font-family:Arial;color:rgb(102,102,102);background-color:rgb(255,255,255);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">We study bisimulation and context equivalence in a probabilistic lambda-calculus. Firstly, we show a technique for proving congruence of probabilistic applicative bisimilarity. While the technique follows Howe's method, some of the technicalities are quite different, relying on non-trivial "disentangling" properties for sets of real numbers. We then analyze the impact the employed notion of reduction has on full-abstraction, giving somewhat surprising results in the call-by-value case. We finally give another unexpected result about the discriminating power of probabilistic contexts on pure lambda-terms.<span class="sew45ltu052xhpc"></span><span class="sewgwbxfwauvec0"></span></span></p>
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