- 95
- 14 301
Igor Khavkine
เข้าร่วมเมื่อ 20 พ.ค. 2010
Lagrangian concordance is not a partial order -- Roman Golovko (Charles University) PHK 04.12.2024
Title: Lagrangian concordance is not a partial order
Speaker: Roman Golovko (Charles University)
Abstract:
We will show that Lagrangian concordance between Legendrian submanifolds is not anti-symmetric, and hence does not define a partial order. Partially it is based on joint work with Georgios Dimitroglou Rizell.
Talk given at the Prague-Hradec Králové seminar on Cohomology in algebra, geometry, physics and statistics:
www.math.cas.cz/index.php/events/event/3825
researchseminars.org/talk/PHK-cohomology-seminar/117/
Speaker: Roman Golovko (Charles University)
Abstract:
We will show that Lagrangian concordance between Legendrian submanifolds is not anti-symmetric, and hence does not define a partial order. Partially it is based on joint work with Georgios Dimitroglou Rizell.
Talk given at the Prague-Hradec Králové seminar on Cohomology in algebra, geometry, physics and statistics:
www.math.cas.cz/index.php/events/event/3825
researchseminars.org/talk/PHK-cohomology-seminar/117/
มุมมอง: 23
วีดีโอ
Homological reduction of Poisson structures -- Pedro H. Carvalho (Hradec Kralove) PHK 20.11.2024
มุมมอง 4621 ชั่วโมงที่ผ่านมา
Title: Homological reduction of Poisson structures Speaker: Pedro H. Carvalho (University of Hradec Kralove) Abstract: From Roytenberg-Ševera, we know that Poisson manifolds are in one-to-one correspondence with symplectic NQ-manifolds of degree one. Cattaneo-Zambon further extended this relation to the level of reduction with their graded geometric approach to Poisson reduction. Based on these...
Conformally homogeneous Lorentzian spaces -- Anton Galaev (Hradec Kralove) PHK 20.11.2024
มุมมอง 4214 วันที่ผ่านมา
Title: Conformally homogeneous Lorentzian spaces Speaker: Anton Galaev (University of Hradec Kralove) Abstract: This is a joint work with Dmitri Alekseevsky. We prove that if a simply connected non-conformally flat conformal Lorentzian manifold $(M,c)$ admits an essential transitive group of conformal transformations, then there exists a metric $g\in c$ such that $(M,g)$ is a complete homogeneo...
On Chern-Losik class for codimension two foliations -- Yaroslav Bazaikin ( nad Labem) PHK 13.11.2024
มุมมอง 3221 วันที่ผ่านมา
Title: On Chern-Losik class for codimension two foliations Speaker: Yaroslav Bazaikin (Jan Evangelista Purkyně University in Ústí nad Labem) Abstract: Losik classes generalize characteristic classes of foliations using Gelfand-Fuchs cohomology approach. The Chern-Losik class for foliations of codimension one was constructed by Losik, and he also showed the non-triviality of this class for a fol...
Combinatorics on Words in Isabelle/HOL -- Štěpán Holub (Charles University) PHK 30.10.2024
มุมมอง 26หลายเดือนก่อน
Title: Combinatorics on Words in Isabelle/HOL Speaker: Štěpán Holub (Charles University) Abstract: The talk will present the ongoing project of formalization of combinatorics on words in the computer proof assistant Isabelle/HOL. Independently of the particular formalized topic, the talk will attempt to serve as an introduction to Isabelle/HOL for beginners. Talk given at the Prague-Hradec Král...
Shadowing of actions of hyperbolic groups on their boundaries -- Michal Doucha (ASCR) PHK 16.10.2024
มุมมอง 33หลายเดือนก่อน
Title: Shadowing of actions of hyperbolic groups on their boundaries Speaker: Michal Doucha (Institute of Mathematics of ASCR) Abstract: I will give a quick introduction to general Gromov hyperbolic metric spaces, in particular hyperbolic groups, and their boundaries. A very useful way of studying hyperbolic groups is via their canonical actions on their boundaries. I will discuss a very recent...
Graded geometry of local gauge theories -- Maxim Grigoriev (Moscow S.U., Mons U.) PHK 09.10.2024
มุมมอง 252 หลายเดือนก่อน
Title: Graded geometry of local gauge theories Speaker: Maxim Grigoriev (Moscow State University and Mons University) Abstract: Gauge PDEs generalize AKSZ sigma models to the case of general local gauge theories. Despite being very flexible and invariant these geometrical objects are usually infinite-dimensional and are difficult to define explicitly, just like standard infinitely-prolonged PDE...
Graded super Hopf algebroids -- Alexei Kotov (University of Hradec Kralove) PHK 02.10.2024
มุมมอง 482 หลายเดือนก่อน
Title: Graded super Hopf algebroids Speaker: Alexei Kotov (University of Hradec Kralove) Abstract: The talk will be focused on Hopf algebras and algebroids in the category of Z-graded varieties. The theory of Harish-Chandra pairs will be briefly discussed and their generalization to action algebroids will be presented. Talk given at the Prague-Hradec Králové seminar on Cohomology in algebra, ge...
On nearly parallel G_2-manifolds -- Alexei Kovalev (Cambridge) PHK 29.05.2024
มุมมอง 676 หลายเดือนก่อน
Title: On nearly parallel G_2-manifolds Speaker: Alexei Kovalev (Cambridge) Abstract: A nearly parallel $G_2$-structure on a 7-manifold can be given by a 3-form $\phi$ of special algebraic type satisfying a differential equation $d\phi = \tau^* \phi$ for a non-zero constant $\tau$. We consider nearly parallel $G_2$-structures on the Aloff Wallach spaces and on regular Sasaki Einstein 7-manifold...
Orbifold constructions of Sasakian structures on SB mflds--A Tralle (Warmia & Mazury) PHK 22.05.2024
มุมมอง 146 หลายเดือนก่อน
Title: Orbifold constructions of Sasakian structures on Smale-Barden manifolds Speaker: Aleksy Tralle (University of Warmia and Mazury) Abstract: Talk given at the Prague-Hradec Králové seminar on Cohomology in algebra, geometry, physics and statistics: www.math.cas.cz/index.php/events/event/3696 researchseminars.org/talk/PHK-cohomology-seminar/104/
An introduction to the classification of C*-algebras -- Karen Strung (IM, ASCR) PHK 24.04.2024
มุมมอง 1377 หลายเดือนก่อน
Title: An introduction to the classification of C*-algebras Speaker: Karen Strung (Institute of Mathematics of ASCR) Abstract: I will give an expository talk about the C*-algebra classification program. In recent years, the following classification theorem was established after years of work by many authors: Theorem: Let A and B be simple, separable, nuclear C*-algebras which tracially absorb t...
The neighborhood of a leaf of a singular foliation -- C. Laurent-Gengoux (Lorraine) PHK 03.04.2024
มุมมอง 448 หลายเดือนก่อน
Title: The neighborhood of a leaf of a singular foliation Speaker: Camille Laurent-Gengoux (Université de Lorraine, IECL) Abstract: Near a leaf, regular foliations are classified by their monodromies. What about the singular leaves of singular foliations? The first point is that for a singular leaf, there is a transverse singular foliation, which is constant all along the leaf. In a previous wo...
Stabilizer limits and Orbit closures, applications to GCT--K V Subrahmanyam (Chennai) PHK 20.03.2024
มุมมอง 158 หลายเดือนก่อน
Title: Stabilizer limits and Orbit closures with applications to Geometric Complexity Theory Speaker: K V Subrahmanyam (Chennai Mathematical Institute) Abstract: Let $G\subseteq GL(X)$ be a reductive group acting on a finite dimensional vector space $V$ over $\C$. A central problem in Geometric Complexity Theory is the study points $y,z\in V$ where (i) $z$ is obtained as the leading term of the...
Virtual Legendrian knots and possible relations to causality -- V.Chernov (Dartmouth) PHK 13.03.2024
มุมมอง 318 หลายเดือนก่อน
Title: Virtual Legendrian knots and possible relations to causality in Borde-Sorkin spacetimes Speaker: Vladimir Chernov (Dartmouth College) Abstract: We review our results with Stefan Nemirovski on the relation of Legendrian linking and causal structure in globally hyperbolic spacetimes. After that we discuss virtual Legendrian knots defined as Legendrian knots in $ST^∗M$ studied up to isotopy...
Koszul-Tate resolutions and trees -- Aliaksandr Hancharuk (Jilin University, China) PHK 06.03.2024
มุมมอง 409 หลายเดือนก่อน
Title: Koszul-Tate resolutions and trees Speaker: Aliaksandr Hancharuk (Jilin University, China) Abstract: Given a commutative algebra O, a proper ideal I, and a resolution of O/I by projective O-modules, we construct an explicit Koszul-Tate resolution. We call it the arborescent Koszul-Tate resolution since it is indexed by decorated trees. When the O-module resolution has finite length, only ...
Z-graded Q-manifolds -- Alexei Kotov (Hradec-Kralove) PHK 21.02.2024
มุมมอง 1089 หลายเดือนก่อน
Z-graded Q-manifolds Alexei Kotov (Hradec-Kralove) PHK 21.02.2024
Conformal IDEAL covariant characterization of Kerr -- A. García-Parrado (Cordoba) PHK 13.12.23
มุมมอง 3311 หลายเดือนก่อน
Conformal IDEAL covariant characterization of Kerr A. García-Parrado (Cordoba) PHK 13.12.23
Unital C_∞-algebras and the real homotopy type of [some] 8-mflds -- H. Van Le (Prague) PHK 06.12.23
มุมมอง 53ปีที่แล้ว
Unital C_∞-algebras and the real homotopy type of [some] 8-mflds H. Van Le (Prague) PHK 06.12.23
Theorem of Lusternik and Schnirelmann for reversible Finsler metrics -- S.Suhr (Bochum) PHK 29.11.23
มุมมอง 127ปีที่แล้ว
Theorem of Lusternik and Schnirelmann for reversible Finsler metrics S.Suhr (Bochum) PHK 29.11.23
Homotopy algebras A(∞), C(∞), B(∞), hGa -- Tornike Kadeishvili (Tbilisi) PHK 22.11.2023
มุมมอง 118ปีที่แล้ว
Homotopy algebras A(∞), C(∞), B(∞), hGa Tornike Kadeishvili (Tbilisi) PHK 22.11.2023
Internal Lagrangians of PDEs -- K. Druzhkov (Russian-Armenian University, Yerevan) PHK 15.11.23
มุมมอง 38ปีที่แล้ว
Internal Lagrangians of PDEs K. Druzhkov (Russian-Armenian University, Yerevan) PHK 15.11.23
From the Mayer-Vietoris spectral sequence to überhomology -- Luigi Caputi (Turin) PHK 01.11.23
มุมมอง 138ปีที่แล้ว
From the Mayer-Vietoris spectral sequence to überhomology Luigi Caputi (Turin) PHK 01.11.23
Homot. types of diff. groups of polar Morse-Bott foliations--S.Maksymenko (NAS Ukraine) PHK 11.10.23
มุมมอง 36ปีที่แล้ว
Homot. types of diff. groups of polar Morse-Bott foliations S.Maksymenko (NAS Ukraine) PHK 11.10.23
An approach to homological algebra up to $\\epsilon$ -- Tobias Fritz (U. Innsbruck), PHK 04.10.2023
มุมมอง 35ปีที่แล้ว
An approach to homological algebra up to $\\epsilon$ Tobias Fritz (U. Innsbruck), PHK 04.10.2023
Real cobordism theory to the Kervaire invariant one problem -- G. Li (Michigan U.), PHK 24.05.2023
มุมมอง 50ปีที่แล้ว
Real cobordism theory to the Kervaire invariant one problem G. Li (Michigan U.), PHK 24.05.2023
Almost invariant differential calculus -- Jan Slovak (Masaryk University), PHK 17.05.2023
มุมมอง 56ปีที่แล้ว
Almost invariant differential calculus Jan Slovak (Masaryk University), PHK 17.05.2023
On 3-nondegenerate CR manifolds in dimension 7 -- Andrea Santi (Rome "Tor Vergata"), PHK 10.05.2023
มุมมอง 93ปีที่แล้ว
On 3-nondegenerate CR manifolds in dimension 7 Andrea Santi (Rome "Tor Vergata"), PHK 10.05.2023
Massey tensors and rational homotopy type of 7- and 8-mfds -- J. Nordström (U. Bath), PHK 03.05.2023
มุมมอง 40ปีที่แล้ว
Massey tensors and rational homotopy type of 7- and 8-mfds J. Nordström (U. Bath), PHK 03.05.2023
On local and global invariants of flat bundles -- Sam Nariman (Purdue University), PHK 26.04.2023
มุมมอง 63ปีที่แล้ว
On local and global invariants of flat bundles Sam Nariman (Purdue University), PHK 26.04.2023
Nonabelian Čech cocycles in noncommutative geometry -- Zoran Škoda (U. Zadar & UHK), PHK 19.04.2023
มุมมอง 37ปีที่แล้ว
Nonabelian Čech cocycles in noncommutative geometry Zoran Škoda (U. Zadar & UHK), PHK 19.04.2023
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Why the 2 dislikes? :(
On second thought, the first version of condition (ii) in the definition of r-fold vector cross product was correct, after all. I checked on Lee-Leung's "Higher dimensional knot spaces for manifolds with vector cross products" and they coincided. But this could of course be a typo in their paper that I had reproduced, so there was the need for an argument for "having a nontrivial kernel does not prevent this condition to be satisfied". And this argument is actually the obvious one (on second thought): condition (ii) is not a condition on every vector in the r-fold exterior product of V but only on decomposable ones. And as such it can indeed be satisfied even in dim(\wedge^r V) > dim(V). It is actually hard to imagine this can actually be possible, and there are indeed just two exceptional situations where this happens. Thanks again, Igor, for having made me notice I had not reflected enough on this point.