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<div dir="ltr">Dear all,</div>
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<div dir="ltr">Just a reminder that we have a DDTG next friday! A nice mix of differential topology and homotopy theory. I’ll see you there!</div>
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<div dir="ltr">Best,</div>
<div dir="ltr">Thomas<br>
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Begin forwarded message:<br>
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<div dir="ltr"><b>From:</b> "Pasquotto, F. (Federica)" <f.pasquotto@math.leidenuniv.nl><br>
<b>Date:</b> 5 December 2025 at 08:00:28 CET<br>
<b>To:</b> "Pasquotto, F. (Federica)" <f.pasquotto@math.leidenuniv.nl><br>
<b>Subject:</b> <b>DDT&G seminar on Friday 12 December in Utrecht: Pedro Boavida de Brito</b><br>
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Dear all, </div>
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You are cordially invited to attend next week's Dutch Differential Topology and Geometry seminar, which will take place in Utrecht. </div>
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<b>Speaker</b>: <a title="https://www.math.tecnico.ulisboa.pt/~pbrito/" class="OWAAutoLink" id="OWAf26c91c9-ef07-01f3-1dc4-9d42518bd58c" href="https://www.math.tecnico.ulisboa.pt/~pbrito/">
Pedro Boavida de Brito</a> (IST Lisbon)</div>
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<b>Title</b>: <i>Smooth embeddings from the point of view of operad theory</i></div>
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<b>Date</b>: Friday 12 December, 14:30-17:00</div>
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<b>Location</b>: Utrecht, KBG-224</div>
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The schedule will be as follows:</div>
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2:30-3:30 p.m.: first part of the seminar (little to no prior knowledge assumed)</div>
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4:00-5:00 p.m.: second part of the seminar (slightly more advanced level)</div>
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Please notice that the first part of the seminar (2:30-3:30 p.m.) is intended for general mathematical audience, and master students with an interest in geometry and topology are especially encouraged to participate.</div>
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Please visit the seminar's webpage for additional information and an overview of past and upcoming talks:</div>
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<span style="color: rgb(0, 0, 0);"><br>
</span><span style="color: blue;"><u><a style="color: blue; margin: 0px;" data-auth="NotApplicable" data-linkindex="1" data-safelink="true" data-loopstyle="linkonly" originalsrc="https://www.few.vu.nl/~trt800/ddtg.html" rel="noopener noreferrer" title="Original URL: https://www.few.vu.nl/~trt800/ddtg.html. Click or tap if you trust this link." class="x_x_x_x_x_x_x_x_x_x_x_ContentPasted1 x_x_x_x_x_x_x_x_x_x_OWAAutoLink x_x_x_x_x_x_x_x_x_x_ContentPasted0 x_x_x_x_x_x_x_x_x_ContentPasted0" id="OWA8118878f-35ba-8fe3-0be9-29dfcd00563a" target="_blank" href="https://www.few.vu.nl/~trt800/ddtg.html">https://www.few.vu.nl/~trt800/</a></u></span><span style="color: rgb(7, 7, 6);"><u><a style="color: rgb(7, 7, 6); margin: 0px;" data-auth="NotApplicable" data-linkindex="2" data-safelink="true" data-loopstyle="linkonly" originalsrc="https://www.few.vu.nl/~trt800/ddtg.html" rel="noopener noreferrer" title="Original URL: https://www.few.vu.nl/~trt800/ddtg.html. Click or tap if you trust this link." class="x_x_x_x_x_x_x_x_x_x_x_ContentPasted1 x_x_x_x_x_x_x_x_x_x_OWAAutoLink x_x_x_x_x_x_x_x_x_x_ContentPasted0 x_x_x_x_x_x_x_x_x_ContentPasted0" id="OWAe46a75db-a4c5-b5d0-0d46-53f06762aab4" target="_blank" href="https://www.few.vu.nl/~trt800/ddtg.html">ddt</a></u></span><span style="color: blue;"><u><a style="color: blue; margin: 0px;" data-auth="NotApplicable" data-linkindex="3" data-safelink="true" data-loopstyle="linkonly" originalsrc="https://www.few.vu.nl/~trt800/ddtg.html" rel="noopener noreferrer" title="Original URL: https://www.few.vu.nl/~trt800/ddtg.html. Click or tap if you trust this link." class="x_x_x_x_x_x_x_x_x_x_x_ContentPasted1 x_x_x_x_x_x_x_x_x_x_OWAAutoLink x_x_x_x_x_x_x_x_x_x_ContentPasted0 x_x_x_x_x_x_x_x_x_ContentPasted0" id="OWAa2529dda-692d-1d77-f2b6-64e6b6408d5c" target="_blank" href="https://www.few.vu.nl/~trt800/ddtg.html">g.html</a></u></span></div>
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We hope to see many of you next week in Utrecht!</div>
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Alvaro, Federica and Thomas</div>
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<b>Abstract</b></div>
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Given two smooth embeddings from one manifold to another, are they isotopic? In the so-called metastable range, Haefliger and Becker showed this problem is controlled by a single cohomology class, a complete obstruction to isotopy. I will explain, with examples,
how embedding calculus generalises this by providing not one but a finite list of obstruction classes which form a complete obstruction to isotopy (when we have convergence).</div>
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In the second part, I will give an account of the formality of the little discs operad and describe recent joint work with Joana Cirici and Geoffroy Horel showing that formality also holds when the orthogonal group action is taken into account. This has striking
consequences to the rational homotopy type of embedding spaces, which I will explain, and extends results of Fresse-Turchin-Willwacher to manifolds which are not parallelized.</div>
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Classified as Internal | Intern</div>
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