[PHK_seminar] [Cohomology]Wednesday 11 Mar, Russell Avdek

[Petr Somberg]

 This is just a gentle reminder of our seminar.

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Od: sender of seminar announcement via phk_seminar <phk_seminar at math.cas.cz>
Komu: phk_seminar at math.cas.cz
Datum: 9. 3. 2026 13:01:16
Předmět: [PHK_seminar] [Cohomology]Wednesday 11 Mar, Russell Avdek
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Wednesday, 11 March 2026 - 13:30 to 14:30
Place: Institute of Mathematics of ASCR, Žitná 25, Praha 1, ZOOM meeting

Speaker: Russell Avdek, Institut de Mathématiques de Jussieu, Sorbonne
Université
Title: Numerical invariants of contact manifolds and their divisors

Abstract


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.

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We shall open the ZOOM meeting at 13.15 for (virtual) coffee and close ZOOM
at 15.00




Join Zoom Meeting




https://cesnet.zoom.us/j/99598413922?pwd=YXNFbk50aVhleXhWSGtISFViLytRUT09
(https://cesnet.zoom.us/j/99598413922?pwd=YXNFbk50aVhleXhWSGtISFViLytRUT09)




Meeting ID:99598413922

Passcode:Galois

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On Wednesday March 18 Hông Vân Lê shall give a talk on Minimal Unital Cyclic
C∞ -Algebras and the Real and Rational Homotopy Types of Closed Manifolds
(https://www.math.cas.cz/index.php/events/event/4151)



For more information see the seminar web page at
https://www.math.cas.cz/index.php/events/seminar/16

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