From phk_seminar_announcement at math.cas.cz Mon Mar 2 13:00:02 2026 From: phk_seminar_announcement at math.cas.cz (phk_seminar_announcement at math.cas.cz) Date: Mon, 02 Mar 2026 12:00:02 +0000 Subject: [PHK_seminar] [Cohomology]Wednesday 4 Mar, Andrey Krutov Message-ID: An HTML attachment was scrubbed... URL: From somberg at karlin.mff.cuni.cz Wed Mar 4 12:12:26 2026 From: somberg at karlin.mff.cuni.cz (Petr Somberg) Date: Wed, 4 Mar 2026 12:12:26 +0100 Subject: [PHK_seminar] [Cohomology]Wednesday 4 Mar, Andrey Krutov In-Reply-To: References: Message-ID: <195.113.30.248.1051.7db1e2602087ee69f69400ce53d23e69.squirrel@webmail.karlin.mff.cuni.cz> This is just a gentle remainder of our seminar! -------------------------------------------------------------------------- > Cohomology in algebra, geometry, physics and statistics > Wednesday, 4 March 2026 - 13:30 to 14:30 > Place: Institute of Mathematics of ASCR, ?itn? 25, Praha 1, the blue > lecture room +ZOOM meeting > > Speaker: Andrey Krutov, Mathematical Institute, Charles University > Title: Non-integrable distributions with simple infinite-dimensional Lie > superalgebra of symmetries Abstract > > > The only simple infinite-dimensional Lie algebras preserving a > non-integrable distribution are the algebras of contact vector fields in > odd dimensions. We formulate analogs of the above statement and prove > them for (super)varieties over algebraically closed fields of any > characteristic $p\geq0$. > > > > > Over fields~$\mathbb{K}$ of characteristic $p>0$, we classify the > Weisfeiler gradings (briefly: W-gradings), those corresponding to a > maximal subalgebra of finite codimension, of the known simple vectorial > Lie (super)algebras with unconstrained shearing vector of heights of the > indeterminates, distinguish W-gradings of (super)algebras preserving > non-integrable distributions. > > > > > Join work with D. Leites and I. Shchepochkina (arXiv:2309.16370) > > > ---------------------------------------------------- > We shall open the seminar room and 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 > > > > Meeting ID:99598413922 > Passcode:Galois > > > -------------------------------------------------------------------- > > > > > > On Wednesday March 11 Russell Avdek shall give a lecture on > Numerical invariants of contact manifolds and their divisors > > > > 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 at math.cas.cz > _______________________________________________ > phk_seminar mailing list phk_seminar at math.cas.cz > https://list.math.cas.cz/listinfo/phk_seminar > > From khavkine at math.cas.cz Wed Mar 4 17:07:23 2026 From: khavkine at math.cas.cz (Igor Khavkine) Date: Wed, 4 Mar 2026 17:07:23 +0100 Subject: [PHK_seminar] [Cohomology]Wednesday 25 Feb, Ida Zadeh In-Reply-To: <93ecdeb34169dfb19e3ab047c472aa1d@math.cas.cz> References: <93ecdeb34169dfb19e3ab047c472aa1d@math.cas.cz> Message-ID: <40768678-314e-452d-9cc9-62ff9454d1a7@math.cas.cz> Dear All, Unfortunately, due to a technical mixup, there is no video recording of the talk by Ida Zadeh from last week. However, the slides from the presentation are available from https://users.math.cas.cz/~hvle/PHK/FioresiGeometricDeepLearning2026.pdf This link has also been recorded at the ResearchSeminars announcement https://researchseminars.org/talk/PHK-cohomology-seminar/148/ Best, Igor On 2/23/26 12:00 PM, sender of seminar announcement via phk_seminar wrote: > Wednesday, 25 February 2026 - 12:15 to 13:15 > Place: Institute of Mathematics of ASCR, ?itn? 25, Praha 1, ZOOM meeting > > Speaker: Ida Zadeh, University of Southampton, UK > Title: Tracking the symmetries of Z3-orbifold K3s within the Mathieu groups > > Abstract > > he goal of this talk is to determine the group of holomorphic symplectic > automorphisms of Z3-orbifold limits of K3 surfaces, and to track this > group within two of the sporadic groups Mathieu 12 and Mathieu 24. To do > so, I will provide a counterpart to the extensive studies by Nikulin and > others of the geometry and symmetries of classical Kummer surfaces, > which involves a variation of Kondo's lattice techniques that Taormina > and Wendland introduced earlier in the genesis of their symmetry surfing > programme. I will realise the finite group of symplectic automorphisms > of this class of K3 surfaces as a subgroup of Mathieu 12 and Mathieu 24 > in terms of permutations of respectively 12 and 24 elements. The talk is > based on a joint work with Kasia Budzik, Anne Taormina, Mara Ungureanu > and Katrin Wendland. > > +++++ > > ------------------------------------------------------ > > This seminar starts *EARLIER * than the usual schedule. > > *We shall open the seminar room + ZOOM meeting at 12.00*for (virtual) > coffee and close ZOOM at 13.30 > > > Join Zoom Meeting > > > https://cesnet.zoom.us/j/99598413922? > pwd=YXNFbk50aVhleXhWSGtISFViLytRUT09 j/99598413922?pwd=YXNFbk50aVhleXhWSGtISFViLytRUT09> > > > Meeting ID:99598413922 > > Passcode:Galois > > > ------------------------------------------------------------------------------------- > > On Wednesday March 4 Andrey Krutov shall give a talk on Non-integrable > distributions with simple infinite-dimensional Lie superalgebra of > symmetries > > > > 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 at math.cas.cz > > > _______________________________________________ > phk_seminar mailing list > phk_seminar at math.cas.cz > https://list.math.cas.cz/listinfo/phk_seminar From phk_seminar_announcement at math.cas.cz Mon Mar 9 13:00:02 2026 From: phk_seminar_announcement at math.cas.cz (phk_seminar_announcement at math.cas.cz) Date: Mon, 09 Mar 2026 12:00:02 +0000 Subject: [PHK_seminar] [Cohomology]Wednesday 11 Mar, Russell Avdek Message-ID: An HTML attachment was scrubbed... URL: From somberg at karlin.mff.cuni.cz Wed Mar 11 10:59:27 2026 From: somberg at karlin.mff.cuni.cz (Petr Somberg) Date: Wed, 11 Mar 2026 10:59:27 +0100 Subject: [PHK_seminar] [Cohomology]Wednesday 11 Mar, Russell Avdek Message-ID: <195.113.30.248.1051.f92514ebeb2862de17a61a8c1186a5b1.squirrel@webmail.karlin.mff.cuni.cz> This is just a gentle reminder of our seminar. ============================================================================ Od: sender of seminar announcement via phk_seminar Komu: phk_seminar at math.cas.cz Datum: 9. 3. 2026 13:01:16 P?edm?t: [PHK_seminar] [Cohomology]Wednesday 11 Mar, Russell Avdek " Wednesday, 11 March 2026 - 13:30 to 14:30 Place: Institute of Mathematics of ASCR, ?itn? 25, Praha 1, ZOOM meeting Speaker: Russell Avdek, Institut de Math?matiques de Jussieu, Sorbonne Universit? 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 H?ng V?n L? 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 at math.cas.cz _______________________________________________ phk_seminar mailing list phk_seminar at math.cas.cz https://list.math.cas.cz/listinfo/phk_seminar " -------------- next part -------------- An HTML attachment was scrubbed... URL: From khavkine at math.cas.cz Mon Mar 16 12:08:54 2026 From: khavkine at math.cas.cz (Igor Khavkine) Date: Mon, 16 Mar 2026 12:08:54 +0100 Subject: [PHK_seminar] [Cohomology]Wednesday 4 Mar, Andrey Krutov In-Reply-To: References: Message-ID: Dear All, The video recording of the recent talk by Andrey Krutov is now available on YouTube at https://youtu.be/pUBbQbkjKM8 Apologies for minor audio problems during recording. The link has also been recorded at the ResearchSeminars announcement https://researchseminars.org/talk/PHK-cohomology-seminar/149/ Best, Igor On 3/2/26 1:00 PM, sender of seminar announcement via phk_seminar wrote: > Wednesday, 4 March 2026 - 13:30 to 14:30 > Place: Institute of Mathematics of ASCR, ?itn? 25, Praha 1, the blue > lecture room +ZOOM meeting > > Speaker: Andrey Krutov, Mathematical Institute, Charles University > Title: Non-integrable distributions with simple infinite-dimensional Lie > superalgebra of symmetries > > Abstract > > The only simple infinite-dimensional Lie algebras preserving a non- > integrable distribution are the algebras of contact vector fields in odd > dimensions. We formulate analogs of the above statement and prove them > for (super)varieties over algebraically closed fields of any > characteristic $p\geq0$. > > > Over fields~$\mathbb{K}$ of characteristic $p>0$, we classify the > Weisfeiler gradings (briefly: W-gradings), those corresponding to a > maximal subalgebra of finite codimension, of the known simple vectorial > Lie (super)algebras with unconstrained shearing vector of heights of the > indeterminates, distinguish W-gradings of (super)algebras preserving > non-integrable distributions. > > > Join?work?with?D.?Leites?and?I.?Shchepochkina?(arXiv:2309.16370) > > ---------------------------------------------------- > > We shall open the seminar room and 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 j/99598413922?pwd=YXNFbk50aVhleXhWSGtISFViLytRUT09> > > > Meeting ID:99598413922 > > Passcode:Galois > > -------------------------------------------------------------------- > > > On Wednesday March 11 Russell Avdek shall give a lecture on Numerical > invariants of contact manifolds and their divisors www.math.cas.cz/index.php/events/event/4130> > > 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 at math.cas.cz > > > _______________________________________________ > phk_seminar mailing list > phk_seminar at math.cas.cz > https://list.math.cas.cz/listinfo/phk_seminar From khavkine at math.cas.cz Mon Mar 16 12:22:26 2026 From: khavkine at math.cas.cz (Igor Khavkine) Date: Mon, 16 Mar 2026 12:22:26 +0100 Subject: [PHK_seminar] [Cohomology]Wednesday 11 Mar, Russell Avdek In-Reply-To: References: Message-ID: <78248e2e-8971-4687-a329-8de619190852@math.cas.cz> 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, ?itn? 25, Praha 1, ZOOM meeting > > Speaker: Russell Avdek, Institut de Math?matiques de Jussieu, Sorbonne > Universit? > 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 j/99598413922?pwd=YXNFbk50aVhleXhWSGtISFViLytRUT09> > > > Meeting ID:99598413922 > > Passcode:Galois > > -------------------------------------------------------------------------------------------------------------------------------- > > On Wednesday March 18 H?ng V?n L? shall give a talk on Minimal Unital > Cyclic C? -Algebras and the Real and Rational Homotopy Types of Closed > Manifolds > > 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 at math.cas.cz > > > _______________________________________________ > phk_seminar mailing list > phk_seminar at math.cas.cz > https://list.math.cas.cz/listinfo/phk_seminar From phk_seminar_announcement at math.cas.cz Mon Mar 16 13:00:02 2026 From: phk_seminar_announcement at math.cas.cz (phk_seminar_announcement at math.cas.cz) Date: Mon, 16 Mar 2026 12:00:02 +0000 Subject: [PHK_seminar] =?utf-8?q?=5BCohomology=5DWednesday_18_Mar=2C_H?= =?utf-8?b?w7RuZyBWw6JuIEzDqg==?= Message-ID: <01e4a42708fe5198a53c338ca499fdff@math.cas.cz> An HTML attachment was scrubbed... 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