<html><body><br><aside>---------- Původní e‑mail ----------<br>Od: sender of seminar announcement via phk_seminar <phk_seminar@math.cas.cz><br>Komu: phk_seminar@math.cas.cz<br>Datum: 9. 3. 2026 13:01:16<br>Předmět: [PHK_seminar] [Cohomology]Wednesday 11 Mar, Russell Avdek</aside><br><blockquote data-email="phk_seminar@math.cas.cz">
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Wednesday, 11 March 2026 - 13:30 to 14:30 <br>
Place: Institute of Mathematics of ASCR, Žitná 25, Praha 1, ZOOM meeting
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Speaker: Russell Avdek, Institut de Mathématiques de Jussieu, Sorbonne Université<br>
Title: Numerical invariants of contact manifolds and their divisors
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Abstract <br>
</p><p><span style="color:rgb(0,0,0)">I will introduce an invariant E(K) of codim=2 contact submanifolds K of a contact manifold (of any dimension), generalizing the self-linking number SL(K) of transverse links in the contact 3-sphere. Extending the observation that SL(L)=1 mod 2 for knots, modular properties E(K) are intimately related to the divisibilities of certain Chern numbers. A generalization of Gompf's d3 invariant of contact 3-manifolds is also defined and used to uncover surprising properties of E(K). These tools provide novel information about Milnor numbers of complex hypersurface singularities.</span></p><p>------------------------------------------------------------------------</p><p><br></p><p class="-wm-ql-align-justify"><span style="color:rgb(34,34,34);background-color:rgb(255,255,255)">We shall open the ZOOM meeting at 13.15 for (virtual) coffee and close ZOOM at 15.00</span></p><p class="-wm-ql-align-justify"><br></p><p class="-wm-ql-align-justify"><span style="color:rgb(34,34,34);background-color:rgb(255,255,255)">Join Zoom Meeting</span></p><p class="-wm-ql-align-justify"><br></p><p class="-wm-ql-align-justify"><a href="https://cesnet.zoom.us/j/99598413922?pwd=YXNFbk50aVhleXhWSGtISFViLytRUT09" rel="noopener noreferrer" style="background-color:rgb(255,255,255);color:rgb(17,85,204)">https://cesnet.zoom.us/j/99598413922?pwd=YXNFbk50aVhleXhWSGtISFViLytRUT09</a></p><p class="-wm-ql-align-justify"><br></p><p class="-wm-ql-align-justify"><span style="color:rgb(34,34,34);background-color:rgb(255,255,255)">Meeting ID:99598413922</span></p><p class="-wm-ql-align-justify"><span style="color:rgb(34,34,34);background-color:rgb(255,255,255)">Passcode:Galois</span></p><p>--------------------------------------------------------------------------------------------------------------------------------</p><p>On Wednesday March 18 Hông Vân Lê shall give a talk on <a href="https://www.math.cas.cz/index.php/events/event/4151" rel="noopener noreferrer"> Minimal Unital Cyclic C∞ -Algebras and the Real and Rational Homotopy Types of Closed Manifolds</a></p>
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For more information see the seminar web page at <br>
https://www.math.cas.cz/index.php/events/seminar/16
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Cohomology in algebra, geometry, physics and statistics mailing list <br>
phk_seminar@math.cas.cz <br>
https://list.math.cas.cz/listinfo/phk_seminar@math.cas.cz
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