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

[Igor Khavkine]

Dear All,

The video recording of the talk by Russell Avdek from last week is now 
available on YouTube at

   https://youtu.be/EilwMnnGZq8

The slides are available from

   https://users.math.cas.cz/~hvle/PHK/Avdekinvariantcodim2contact2026.pdf

Both links have also been recorded at the ResearchSeminars announcement

   https://researchseminars.org/talk/PHK-cohomology-seminar/150/

Best,

Igor

On 3/9/26 1:00 PM, sender of seminar announcement via phk_seminar wrote:
> 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.
> 
> ------------------------------------------------------------------------
> 
> 
> 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
> 
> --------------------------------------------------------------------------------------------------------------------------------
> 
> 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
> 
> Cohomology in algebra, geometry, physics and statistics mailing list
> phk_seminar at math.cas.cz
> https://list.math.cas.cz/listinfo/phk_seminar@math.cas.cz
> 
> 
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