Past Events

Moduli and Friends Seminar: this week’s talks

Two talks in the seminar series “Moduli and Friends”, the working seminar of the grant project PCE-2020-2798. Contact person: Martin Palmer-Anghel (mpanghel@imar.ro) Seminar webpage: https://mdp.ac/pce2020/seminar.html Location: online (connection details on request) Thursday, June 17, 2021, 15:00 EEST (UTC+3) Title: Configuration spaces and embedding calculus, I Speaker: Geoffroy Horel (Université Sorbonne Paris Nord) Thursday, June 17,Continue reading “Moduli and Friends Seminar: this week’s talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 15 June 2021, 11:00 GMT.Speaker: Eveline Legendre (University of Toulouse)Title: Valuative stability for polarised varieties Abstract: I will talk about a recent joint work with Ruadhai Dervan where we introduced a notion of valuative stability for polarised variety. This extendsContinue reading “ZAG Seminar: this week talks”

Moduli and Friends Seminar: this week’s talks

Two talks in the seminar series “Moduli and Friends”, the working seminar of the grant project PCE-2020-2798. Contact person: Martin Palmer-Anghel (mpanghel@imar.ro) Seminar webpage: https://mdp.ac/pce2020/seminar.html Location: online (connection details on request) Wednesday, June 9, 2021, 15:00 EEST (UTC+3) Title: Line arrangements, some combinatorial perspectives, II Speaker: Anca Măcinic (IMAR) Wednesday, June 9, 2021, 16:30 EESTContinue reading “Moduli and Friends Seminar: this week’s talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 8 June 2021, 15:00 GMT.Speaker: Lev Borisov (Rutgers University)Title: Explicit equations of surfaces of general type Abstract: I will talk about progress in finding equations of special surfaces of general type, notably fake projective planes. This work was done overContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: Moduli spaces of high-dimensional discs V

Talk in the Seminar Geometric Methods in Algebra and Topology (Zoom session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Zoom link please contact Cristian Anghel (Cristian.Anghel@imar.ro). Friday, June 11, 2021, 14:30-16:00 Title: Moduli spaces of high-dimensional discs V Speaker: Martin Palmer (IMAR) Abstract: This is the 5th in a series of 5 talks, see the full abstractContinue reading “GeMAT Seminar: Moduli spaces of high-dimensional discs V”

Operator Theory Seminar: Entanglement criteria in quantum information theory

Wednesday, June 9th, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Maria Jivulescu (Politehnica University, Timisoara) Title: Entanglement criteria in quantum information theory Abstract: In my talk I will recall basic facts about separable/entanglement quantum states and the main classical criteria for distinguish them. Then I will focus on a new introducedContinue reading “Operator Theory Seminar: Entanglement criteria in quantum information theory”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 1 June 2021, 11:00 GMT.Speaker: Livia Campo (University of Birmingham)Title: Fano 3-folds and double covers Abstract: I will propose a method to explicitly construct 52 deformation families of terminal Q-Fano 3-folds in codimension 4 and Fano index 2. Their structureContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: Moduli spaces of high-dimensional discs IV

Talk in the Seminar Geometric Methods in Algebra and Topology (Zoom session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Zoom link please contact Cristian Anghel (Cristian.Anghel@imar.ro). Friday, June 4, 2021, 14:30-16:00 Title: Moduli spaces of high-dimensional discs IV Speaker: Martin Palmer (IMAR) Abstract: This is the 4th in a series of 5 talks, see the full abstractContinue reading “GeMAT Seminar: Moduli spaces of high-dimensional discs IV”

Operator Theory Seminar: Index theory for tensor products of pseudodifferential operators

Wednesday, June 2nd, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Karsten Bohlen (Regensburg) Title: Index theory for tensor products of pseudodifferential operators Abstract: In this talk we consider systems of tensor products of pseudodifferential operators. Motivating examples are double Cauchy integral operators that occur in the study of certain boundary valueContinue reading “Operator Theory Seminar: Index theory for tensor products of pseudodifferential operators”

Moduli and Friends Seminar: this week talks

Two talks in the seminar series “Moduli and Friends”, the working seminar of the grant project PCE-2020-2798. Contact person: Martin Palmer-Anghel (mpanghel@imar.ro) Seminar webpage: https://mdp.ac/pce2020/seminar.html Location: online (connection details on request) Wednesday, May 26, 2021, 15:00 EEST (UTC+3) Title: Line arrangements, some combinatorial perspectives, I Speaker: Anca Măcinic (IMAR) Wednesday, May 26, 2021, 16:30 EESTContinue reading “Moduli and Friends Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 25 May 2021, 15:00 GMT.Speaker: Brendan Hassett (Brown University)Title: Rationality of even-dimensional intersections of two real quadrics Abstract: We consider rationality constructions for smooth complete intersections of two quadrics over nonclosed fields. Over the real numbers, we establish a criterionContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: Moduli spaces of high-dimensional discs III

Talk in the Seminar Geometric Methods in Algebra and Topology (Zoom session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Zoom link please contact Cristian Anghel (Cristian.Anghel@imar.ro). Friday, May 28, 2021, 14:30-16:00 Title: Moduli spaces of high-dimensional discs III Speaker: Martin Palmer (IMAR) Abstract: This is the 3rd in a series of 5 talks, see the full abstractContinue reading “GeMAT Seminar: Moduli spaces of high-dimensional discs III”

Dynamics of germs of diffeomorphisms with semi-neutral behavior

Wednesday, May 19th, 2021, 01:00 PM Bucharest A presentation given at the IMAR Monthly Lecture. Speaker: Remus Radu (IMAR) Title: Dynamics of germs of diffeomorphisms with semi-neutral behavior Abstract: Siegel compacta (or hedgehogs) in dimension one were introduced by Yoccoz and Pérez-Marco in the ’90s to study linearization properties and dynamics of holomorphic univalent germsContinue reading “Dynamics of germs of diffeomorphisms with semi-neutral behavior”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 18 May 2021, 11:00 GMT.Speaker: Jørgen Vold Rennemo (University of Oslo)Title: K-theoretic sheaf counting invariants on C^4 Abstract: Oh and Thomas have recently defined a K-theoretic sheaf counting invariant for moduli spaces of sheaves on a Calabi-Yau 4-fold. One ofContinue reading “ZAG Seminar: this week talks”

Operator Theory Seminar: Entrywise positivity preservers: connections to analysis, covariance estimation, and combinatorics

Wednesday, May 19, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Apoorva Khare (Indian Institute of Science, and Analysis & Probability Research Group, Bangalore) Title: Entrywise positivity preservers: connections to analysis, covariance estimation, and combinatorics Abstract: Which functions preserve positive semidefiniteness (psd) when applied entrywise to psd matrices? This question has aContinue reading “Operator Theory Seminar: Entrywise positivity preservers: connections to analysis, covariance estimation, and combinatorics”

Topology Seminar: Tropical upper bounds for the BNSR invariants

Friday, May 21, 2021, 16:30 (Bucharest time), on Zoom A presentation given at the Topology Seminar. The Zoom link is going to be announced next week by mail. Speaker: Alex Suciu (Northeastern University) Title: Tropical upper bounds for the BNSR invariants Abstract: The Bieri-Neumann-Strebel-Renz invariants are the vanishing loci for the Novikov-Sikorav homology of aContinue reading “Topology Seminar: Tropical upper bounds for the BNSR invariants”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 11 May 2021, 13:00 GMT.Speaker: Stefan Kebekus (University of Freiburg)Title: Brauer-Manin obstruction on a simply connected fourfold and a Mordell theorem in the orbifold setting Abstract: Almost one decade ago, Poonen constructed the first examples of algebraic varieties over globalContinue reading “ZAG Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 4 May 2021, 14:00 GMT.Speaker: María Pe Pereira (Universidad Complutense de Madrid)Title: Moderately Discontinuous Algebraic Topology Abstract: An algebraic or complex analytic subset in has 2 natural metrics: the outer metric (restriction of the euclidean metric) and the inner metricContinue reading “ZAG Seminar: this week talks”

Operator Theory Seminar: A constructive approach to Schäffer’s conjecture

Wednesday, May 12, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Rachid Zarouf (Institut de Mathématiques de Marseille) Title: A constructive approach to Schäffer’s conjecture Abstract: We prove results that we found on our way to a deeper understanding of Schäffer’s conjecture about inverse operators. In 1970 J.J. Schäffer proved that forContinue reading “Operator Theory Seminar: A constructive approach to Schäffer’s conjecture”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Zoom session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Zoom link please contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, May 6, 2021, 14:00-15:30 Title: Hodge cycles for cubic hypersurfaces Speaker: Hossein Movasati (IMPA) Abstract: Despite the abundant examples of Hodge cycles in the literature, finding them for smooth hypersurfacesContinue reading “GeMAT Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 27 April 2021, 15:00 GMT.Speaker: Yuri Tschinkel (Courant Institute, NYU)Title: Equivariant birational types Abstract: I will discuss joint work with A. Kresch and B. Hassett concerning new invariants in equivariant birational geometry and their applications. Zoom Meeting ID: 991 849Continue reading “ZAG Seminar: this week talks”

Operator Theory Seminar: Free spectrahedra and compatibility of quantum measurements

Wednesday, April 28, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Ion Nechita (University of Toulouse) Title: Free spectrahedra and compatibility of quantum measurements Abstract: I will start by reviewing (free) spectrahedra, central objects in free convex analysis. I will then introduce the notion of measurement incompatibility in quantum information theory, andContinue reading “Operator Theory Seminar: Free spectrahedra and compatibility of quantum measurements”

GeMAT Seminar: On the lattice points count on the moduli space of curves II

Talk in the Seminar Geometric Methods in Algebra and Topology (Zoom session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Zoom link please contact Cristian Anghel (Cristian.Anghel@imar.ro). Friday, April 23, 2021, 15:30-17:00 Title: On the lattice points count on the moduli space of curves II Speaker: Olivia Dumitrescu (UNC at Chapel Hill) Abstract: Ribbon graphs are combinatorial objectsContinue reading “GeMAT Seminar: On the lattice points count on the moduli space of curves II”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 20 April 2021, 17:00 GMT.Speaker: Jakub Witaszek (University of Michigan)Title: Relative semiampleness in mixed characteristic Abstract: In this talk we will discuss the existence of contractions and base point freeness of line bundles in mixed characteristic in the context ofContinue reading “ZAG Seminar: this week talks”

Operator Theory Seminar: Spectrum and analytic functional calculus for Clifford operators via stem functions

Wednesday, April 21, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Florian-Horia Vasilescu (University of Lille) Title: Spectrum and analytic functional calculus for Clifford operators via stem functions Abstract: The main purpose of this work is the construction of an analytic functional calculus for Clifford operators, which act on certain modules overContinue reading “Operator Theory Seminar: Spectrum and analytic functional calculus for Clifford operators via stem functions”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 13 April 2021, 17:00 GMT.Speaker: Karl Schwede (University of Utah)Title: Recent progress in mixed characteristic higher dimensional algebraic geometry Abstract: In characteristic zero birational algebraic geometry, Kawamata-Viehweg vanishing is a centrally important tool. For some applications in characteristic p >Continue reading “ZAG Seminar: this week talks”

GeMAT Seminar: On the lattice points count on the moduli space of curves

Talk in the Seminar Geometric Methods in Algebra and Topology (Zoom session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Zoom link please contact Cristian Anghel (Cristian.Anghel@imar.ro). Friday, April 16, 2021, 15:30-17:00 Title: On the lattice points count on the moduli space of curves Speaker: Olivia Dumitrescu (UNC at Chapel Hill) Abstract: Ribbon graphs are combinatorial objects firstContinue reading “GeMAT Seminar: On the lattice points count on the moduli space of curves”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 6 April 2021, 10:00 GMT.Speaker: Takehiko Yasuda (Osaka University)Title: Stringy motives and local fundamental groups of klt surface singularities in arbitrary characteristic Abstract: In this talk, I will speak about an application of stringy motives to local fundamental groups ofContinue reading “ZAG Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 30 March 2021, 10:00 GMT.Speaker: Katsuhisa Furukawa (Josai University)Title: On the singular loci of higher secant varieties of Veronese embeddings Abstract: For a projective variety X in , the k-secant variety is defined to be the closure of the unionContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: Fuchsian sl(2,C)-systems on compact Riemann surfaces

Talk in the Seminar Geometric Methods in Algebra and Topology (Zoom session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Zoom link please contact Cristian Anghel (Cristian.Anghel@imar.ro). Friday, March 26, 2021, 14:30-16:00 Title: Fuchsian sl(2,C)-systems on compact Riemann surfaces Speaker: Sorin Dumitrescu (Université Côte d’Azur) Abstract: For every integer g≥2 we show the existence of a compact RiemannContinue reading “GeMAT Seminar: Fuchsian sl(2,C)-systems on compact Riemann surfaces”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 23 March 2021, 13:00 GMT.Speaker: John Lesieutre (Pennsylvania State University)Title: Rational surface automorphisms without periodic curves Abstract: Although there are many examples known of infinite-order automorphisms of rational surfaces, in most cases these automorphisms have at least one periodic curveContinue reading “ZAG Seminar: this week talks”

Operator Theory Seminar: Topological obstructions to matrix stability of discrete groups

Wednesday, March 24, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Marius Dadarlat (Purdue University) Title: Topological obstructions to matrix stability of discrete groups Abstract: A discrete countable group is matricially stable if its finite dimensional approximate unitary representations are perturbable to genuine representations in the point-norm topology. We aim to explainContinue reading “Operator Theory Seminar: Topological obstructions to matrix stability of discrete groups”

Operator Theory Seminar: Separable boundaries for non-hyperbolic groups

Wednesday, March 17 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Jacopo Bassi (Rome) Title: Separable boundaries for non-hyperbolic groups Abstract: Ozawa proved in 2007 that the nuclear C*-algebra associated to the action of a free group on its boundary sits inside the injective envelope of the reduced C*-algebra of the groupContinue reading “Operator Theory Seminar: Separable boundaries for non-hyperbolic groups”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 16 March 2021, 10:00 GMT.Speaker: Taro Sano (Kobe University)Title: Birational boundedness of some Calabi-Yau hypersurfaces Abstract: It is well-known that complex projective K3 surfaces are connected by analytic deformations, but they are algebraically unbounded. Nevertheless, Reid, Iano-Fletcher and Kollar-Johnson showedContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: Rozansky-Witten theories with noncompact targets

Talk in the Seminar Geometric Methods in Algebra and Topology (Zoom session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Zoom link please contact Cristian Anghel (Cristian.Anghel@imar.ro). Friday, March 12, 2021, 13:00-14:30 Title: Rozansky-Witten theories with noncompact targets Speaker: Hiraku Nakajima (Klavi IPMU) Abstract: A few years ago, I proposed a mathematical definition of Coulomb branches of 3dContinue reading “GeMAT Seminar: Rozansky-Witten theories with noncompact targets”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 9 March 2021, 11:00 GMT.Speaker: Shunsuke Takagi (University of Tokyo)Title: Deformations of F-pure and F-regular singularities Abstract: F-regular and F-pure singularities are singularities in positive characteristic defined in terms of Frobenius splitting properties. Ma and Schwede recently proved that aContinue reading “ZAG Seminar: this week talks”

Operator Theory Seminar: Wold decompositions for representations of C*-algebras associated with noncommutative varieties

Wednesday, March 10, 18:00 (note the unusual time!) A presentation given at the Operator theory seminar. Speaker: Gelu Popescu (San Antonio) Title: Wold decompositions for representations of C*-algebras associated with noncommutative varieties Zoom link: https://us02web.zoom.us/j/83812857092?pwd=bDJGeDBZM0VjMjZoQzdqL3dQcGV2UT09 Password communicated on demand. Contact person: Dan Timotin (dan.timotin@gmail.com)

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 2 March 2021, 15:00 GMT.Speaker: Fernando Cukierman (Universidad de Buenos Aires)Title: Deformations of exterior differential ideals and applications Abstract: The main theme of this talk is the geometry of moduli spaces of algebraic singular foliations on smooth projective algebraic varietiesContinue reading “ZAG Seminar: this week talks”

Operator Theory Seminar: Geometry of weakly invariant norms in skew-Hermitian and Unitary matrices

Wednesday, March 3, 15:00 A presentation given at the Operator theory seminar. Speaker: Gabriel Larotonda (Buenos Aires) Title: Geometry of weakly invariant norms in skew-Hermitian and Unitary matrices Abstract: An Ad-invariant norm in the space of skew-Hermitian matrices (also known as a w.i.n. “weakly invariant norm”) is a vector space norm such that |UVU^*|=|V| forContinue reading “Operator Theory Seminar: Geometry of weakly invariant norms in skew-Hermitian and Unitary matrices”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 23 February 2021, 15:00 GMT.Speaker: Shing-Tung Yau (Harvard University)Title: Geometry of Conifold Transitions Abstract: Conifold transitions were introduced by Clemens, Reid and Friedman to connect Calabi-Yau threefolds with different topologies. However, this operation may produce a complex manifold with trivialContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, February 25, 2021, 14:00-15:30 Title: Introduction to flat and Higgs bundles XIV Speaker: Cristian Anghel (IMAR) Friday, February 26, 2021, 14:30-16:00 Title: Foliations and characteristicContinue reading “GeMAT Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 16 February 2021, 11:00 GMT.Speaker: Yusuke Nakamura (University of Tokyo)Title: Inversion of adjunction for quotient singularities Abstract: The minimal log discrepancy is an invariant of singularities defined in birational geometry, and it is related to the conjecture of termination ofContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, February 18, 2021, 14:30-16:00 Title: Introduction to flat and Higgs bundles XIII Speaker: Cristian Anghel (IMAR) Friday, February 19, 2021, 14:30-16:00 Title: Foliations and characteristicContinue reading “GeMAT Seminar: this week talks”

Operator Theory Seminar: The column-row property for complete Pick spaces

Wednesday, February 17, 15:00 A presentation given at the Operator theory seminar. Speaker: Michael Hartz (Saarbrucken) Title: The column-row property for complete Pick spaces Abstract: Complete Pick spaces form a class of Hilbert function spaces including the Hardy space on the disc, the classical Dirichlet space and also the Drury-Arveson space on the ball. TheyContinue reading “Operator Theory Seminar: The column-row property for complete Pick spaces”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 09 February 2021, 11:00 GMT.Speaker: Enrica Floris (Université de Poitiers)Title: Connected algebraic groups acting on Fano fibrations over P1 Abstract: Let G be a connected algebraic group and X a variety endowed with a regular action of G and aContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, February 11, 2021, 15:30-17:00 Title: Introduction to flat and Higgs bundles XII Speaker: Cristian Anghel (IMAR) Friday, February 12, 2021, 14:30-16:00 Title: Foliations and characteristicContinue reading “GeMAT Seminar: this week talks”

Operator Theory Seminar: Minimal dynamical systems, C*-algebras, and the classification program

Wednesday, February 10, 15:00 A presentation given at the Operator theory seminar. Speaker: Karen Strung (Prague) Title: Minimal dynamical systems, C*-algebras, and the classification program Abstract: This talk is based on joint work with Robin Deeley and Ian Putnam, where we study the existence of minimal dynamical systems, their orbit and minimal orbit-breaking equivalence relations,Continue reading “Operator Theory Seminar: Minimal dynamical systems, C*-algebras, and the classification program”

GeMAT Seminar: On arithmetic Dijkgraaf-Witten theory

Talk in the Seminar Geometric Methods in Algebra and Topology Seminar webpage: https://sites.google.com/site/gematseminar/ Friday, February 05, 2021, 13:30-15:00 Title: On arithmetic Dijkgraaf-Witten theory Speaker: Masanori Morishita (Kyushu University) Abstract: We present some basic constructions and properties in arithmetic Chern-Simons theory, which was initiated by Minhyong Kim, with finite gauge group along the line of topologicalContinue reading “GeMAT Seminar: On arithmetic Dijkgraaf-Witten theory”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 02 February 2021, 15:00 GMT.Speaker: Simon Donaldson (Imperial College London and Simons Center for Geometry and Physics)Title: Enumerative geometry, Fredholm analysis and moduli spaces of surfaces of general type Abstract: In the first part of the talk we will reviewContinue reading “ZAG Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 26 January 2021, 14:00 GMT.Speaker: Frances Kirwan (University of Oxford)Title: Moduli of unstable objects in algebraic geometry Abstract: The construction of the moduli spaces of stable curves of fixed genus is one of the classical applications of Mumford’s geometric invariantContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, January 28, 2021, 15:30-17:00 Title: Introduction to flat and Higgs bundles XI Speaker: Cristian Anghel (IMAR) Friday, January 29, 2021, 14:30-16:00 Title: Cohomology of LieContinue reading “GeMAT Seminar: this week talks”

Operator Theory Seminar: Distinguished Varieties

Wednesday, January 27th, 15:00 A presentation given at the Operator theory seminar. Speaker: Tirthankar Bhattacharyya (Indian Institute of Science, Bangalore) Title: Distinguished Varieties Abstract: The distinguished varieties in the bidisc are algebraic objects. They gained importance in the theory of operators on Hilbert spaces because of the landmark paper MR2231339 by Agler and McCarthy. AndoContinue reading “Operator Theory Seminar: Distinguished Varieties”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 19 January 2021, 09:00 GMT.Speaker: Shihoko Ishii (University of Tokyo)Title: Uniform bound of the number of weighted blow-ups to compute the minimal log discrepancy for smooth 3-folds Abstract: In the talk I will show that the minimal log discrepancy ofContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, January 21, 2021, 15:30-17:00 Title: Introduction to flat and Higgs bundles X Speaker: Cristian Anghel (IMAR) Friday, January 22, 2021, 14:30-16:00 Title: Cohomology of LieContinue reading “GeMAT Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 12 January 2021, 18:00 GMT.Speaker: Patricio Gallardo (UC Riverside)Title: Compactifications of the moduli space of cubic surfaces Abstract: We discuss the interplay between geometric and Hodge theoretical compactifications for the moduli space of cubic surfaces. In particular, we prove thatContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, January 14, 2021, 15:30-17:00 Title: Introduction to flat and Higgs bundles IX Speaker: Cipriana Anghel (IMAR) Friday, January 15, 2021, 14:30-16:00 Title: Cohomology of LieContinue reading “GeMAT Seminar: this week talks”

ZAG Seminar: Key varieties for prime Q-Fano threefolds of codimension 4

Dear ZAG subscribers, Happy New Year! This week we only have one talk. Thursday, 7 January 2021, 10:00 GMT.Speaker: Hiromichi Takagi (Gakushuin University)Title: Key varieties for prime Q-Fano threefolds of codimension 4 Abstract: I talk about my construction of key varieties for prime Q-Fano threefolds of codimension 4 related with -fibrations. I discuss their relationsContinue reading “ZAG Seminar: Key varieties for prime Q-Fano threefolds of codimension 4”

ZAG Seminar: The ACC for local volumes and boundedness of singularities

ZAG is taking a ‘New Year Break’. There will be no talks between 30th December and 6th January. Therefore next week we are only holding one talk. We wish all algebraic geometers happy holidays. 🙂 Tuesday, 29 December 2020, 15:00 GMT.Speaker: Jingjun Han (Johns Hopkins University)Title: The ACC for local volumes and boundedness of singularitiesContinue reading “ZAG Seminar: The ACC for local volumes and boundedness of singularities”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 22 December 2020, 15:00 GMT.Speaker: Han-Bom Moon (Fordham University)Title: Point configurations, phylogenetic trees, and dissimilarity vectors Abstract: In 2004 Pachter and Speyer introduced the dissimilarity maps for phylogenetic trees and asked two important questions about their relationship with tropical Grassmannian.Continue reading “ZAG Seminar: this week talks”

Applications of Alexandrov’s Gluing Theorem to Polyhedral Convex Surfaces

Wednesday, December 23rd, 2020, 01:00 PM Bucharest A presentation given at the IMAR Monthly Seminar. Speaker: Costin Vîlcu (IMAR) Title: Applications of Alexandrov’s Gluing Theorem to Polyhedral Convex Surfaces Abstract: The goal of this talk is to briefly present, without technical details, applications of Alexandrov’s Gluing Theorem to the geometry of polyhedral convex surfaces. AfterContinue reading “Applications of Alexandrov’s Gluing Theorem to Polyhedral Convex Surfaces”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, December 17, 2020, 15:30-17:00 Title: Introduction to flat and Higgs bundles VIII Speaker: Cristian Anghel (IMAR) Friday, December 18, 2020, 14:30-16:00 Title: Cohomology of LieContinue reading “GeMAT Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 15 December 2020, 11:00 GMT.Speaker: Sho Tanimoto (Kumamoto University)Title: Rational curves on Fano threefolds Abstract: Mori proved that a smooth Fano variety contains a lots of rational curves using famous Bend and Break technique. Thus it is natural to studyContinue reading “ZAG Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 8 December 2020, 11:00 GMT.Speaker: Keiji Oguiso (University of Tokyo)Title: Smooth projective rational varieties with non-finitely generated discrete automorphism group Abstract: It is quite recent that smooth complex projective varieties X with non-finitely generated discrete automorphism group Aut(X) were foundContinue reading “ZAG Seminar: this week talks”

Operator Theory Seminar: Some applications of the joint numerical range

Wednesday, December 9th, 15:00 A presentation given at the Operator theory seminar. Speaker: Vladimir Muller (Inst. of Math., Prague) Title: Some applications of the joint numerical range Abstract: We discuss properties of the joint numerical range of operators and show that it can be applied in various situations. In particular, we derive a wide generalizationContinue reading “Operator Theory Seminar: Some applications of the joint numerical range”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, December 10, 2020, 15:30-17:00 Title: Introduction to flat and Higgs bundles VII Speaker: Cristian Anghel (IMAR) Friday, December 11, 2020, 14:30-16:00 Title: Cohomology of LieContinue reading “GeMAT Seminar: this week talks”

Topology Seminar: Groups related to mapping class groups of infinite type surfaces

The IMAR Topology Seminar Friday, December 11th, 2020, 11:00 Speaker: Louis Funar (CNRS-Universite Grenoble Alpes) Title: Groups related to mapping class groups of infinite type surfaces Abstract: The group of C^1 diffeomorphisms of sparse Cantor subsets of a manifold are countable and discrete. We can obtain this way Thompson’s groups and Brin’s higher dimensional generalizations.Continue reading “Topology Seminar: Groups related to mapping class groups of infinite type surfaces”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 1 December 2020, 10:00 GMT.Speaker: Takuzo Okada (Saga University)Title: K-stability of birationally superrigid Fano 3-fold weighted hypersurfaces Abstract: For Fano varieties, birational superrigidity and K-stability are completely different notions. On the other hand, they are both related to mildness ofContinue reading “ZAG Seminar: this week talks”

Moscow-Beijing Topology seminar: On the different flavours of Lawrence-Bigelow representations

Wednesday 2 December 2020, 10:30am Moscow time (9:30am Bucharest time) Invited talk at the Moscow-Beijing Topology seminar. Speaker: Martin Palmer-Anghel (IMAR) Title: On the different flavours of Lawrence-Bigelow representations Abstract: The family of Lawrence-Bigelow representations of the braid groups are of central importance in the study of the braid groups themselves, as well as theirContinue reading “Moscow-Beijing Topology seminar: On the different flavours of Lawrence-Bigelow representations”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, December 3, 2020, 15:30-17:00 Title: Introduction to flat and Higgs bundles VI Speaker: Cristian Anghel (IMAR) Friday, December 4, 2020, 14:30-16:00 Title: Braid group actionContinue reading “GeMAT Seminar: this week talks”

Topology Seminar: Braided surfaces and their characteristic maps

The IMAR Topology Seminar Friday, December 4th, 2020, 11:00 Speaker: Louis Funar (CNRS-Universite Grenoble Alpes) Title: Braided surfaces and their characteristic maps Abstract: Our aim is to show that branched coverings of surfaces of large enough genus arise as characteristic maps of braided surfaces. In the reverse direction we show that any nonabelian surface groupContinue reading “Topology Seminar: Braided surfaces and their characteristic maps”

ZAG Seminar: this week talks

( ZAG seminar ) This week we have a Japanese week! 🇯🇵 And the speakers’ institutions are permutations of each other 😉 Tuesday, 24 November 2020, 10:00 GMT.Speaker: Kazushi Ueda (University of Tokyo)Title: Noncommutative del Pezzo surfaces Abstract: We introduce the notion of noncommutative del Pezzo surfaces, and show that a collection of 12-d generalContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, November 26, 2020, 15:30-17:00 Title: Introduction to flat and Higgs bundles V Speaker: Cristian Anghel (IMAR) Friday, November 27, 2020, 14:30-16:00 Title: Total positivity andContinue reading “GeMAT Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Scroll down for The Whittaker Lecture by Yuri Tschinkel. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 17 November 2020, 15:00 GMT.Speaker: Michela Artebani (Universidad de Concepción)Title: Cox rings of K3 surfaces Abstract: Given a normal complex projective variety X with finitely generated divisor class group, its CoxContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, November 19, 2020, 15:30-17:00 Title: Introduction to flat and Higgs bundles IV Speaker: Cristian Anghel (IMAR) Friday, November 20, 2020, 14:30-16:00 Title: Total positivity andContinue reading “GeMAT Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 10 November 2020, 15:00 GMT.Speaker: Aleksandr Pukhlikov (University of Liverpool)Title: Rationally connected rational double covers of primitive Fano varieties Abstract: We show that for a Zariski general hypersurface of degree in for there are no Galois rational covers with anContinue reading “ZAG Seminar: this week talks”

Topology Seminar: Generalized Dehn twists on surfaces and surgeries in 3-manifolds

The IMAR Topology Seminar Tuesday, November 24, 2020, 11:00 Title: Generalized Dehn twists on surfaces and surgeries in 3-manifolds Abstract: (Joint work with Yusuke Kuno.) Given an oriented surface S and a simple closed curve C in S, the “Dehn twist” along C is the homeomorphism of S defined by “twisting” S around C byContinue reading “Topology Seminar: Generalized Dehn twists on surfaces and surgeries in 3-manifolds”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, November 12, 2020, 15:30-17:00 Title: Introduction to flat and Higgs bundles III Speaker: Cristian Anghel (IMAR) Friday, November 13, 2020, 14:30-16:00 Title: Total positivity andContinue reading “GeMAT Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 3 November 2020, 17:00 GMT.Speaker: Bianca Viray (University of Washington)Title: On quadratic points on intersections of two quadrics Abstract: Springer’s theorem and the Amer-Brumer theorem together imply that intersections of two quadrics have a rational point if and only ifContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, November 5, 2020, 15:30-17:00 Title: Introduction to flat and Higgs bundles II Speaker: Cristian Anghel (IMAR) Friday, November 6, 2020, 14:30-16:00 Title: Total positivity andContinue reading “GeMAT Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 27 October 2020, 16:00 GMT.Speaker: Daniel Greb (University of Duisburg-Essen)Title: Projective flatness over klt spaces and uniformisation of varieties with nef anti-canonical divisor Abstract: I will discuss a criterion for the projectivisation of a reflexive sheaf on a klt spaceContinue reading “ZAG Seminar: this week talks”

GeMAT Seminar: this week talks

Talks in the Seminar Geometric Methods in Algebra and Topology (Skype session) Seminar webpage: https://sites.google.com/site/gematseminar/ For the Skype link please use the usual one, or contact Cristian Anghel (Cristian.Anghel@imar.ro). Thursday, October 29, 2020, 15:30-17:00 Title: Introduction to flat and Higgs bundles Speaker: Cristian Anghel (IMAR) Friday, October 30, 2020, 14:30-16:00 Title: Total positivity and clusterContinue reading “GeMAT Seminar: this week talks”

ZAG Seminar: this week talks

This week we will have two ZAG seminar talks. Contact person: Florin Ambro (florin.ambro@imar.ro) Tuesday, 20 October 2020, 15:00 GMT.Speaker: Gergely Berczi (Aarhus University)Title: Non-reductive group actions and hyperbolicity Abstract: Non-reductive reparametrisation group actions play central role in hyperbolicity questions. Using recently developed intersection theory on non-reductive geometric invariant theory-type quotients and following the strategyContinue reading “ZAG Seminar: this week talks”

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