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PRODID:calendar.unige.ch
VERSION:2.0
CALSCALE:GREGORIAN
X-WR-TIMEZONE:Europe/Zurich
BEGIN:VEVENT
DTSTART:20230511T141500Z
DTEND:20230511T141500Z
DTSTAMP:20240224T185634Z
UID:36495@calendar.unige.ch
CREATED:20230502T154407Z
LAST-MODIFIED:20230504T101050Z
SUMMARY:A modified Hodge conjecture (Dustin Clausen, University of Copenhagen)
DESCRIPTION:The Hodge conjecture, for a smooth projective variety over the complex numbers, gives a criterion on a cohomology class for it to be realized by algebraic cycles. But who knows --- maybe it's false! I will give an introduction to the Hodge conjecture, and then propose a modification, stronger in some ways and weaker in others, which is hopefully easier to prove. This is based on joint work with Peter Scholze.\n\nP.S. The Colloquium will be followed by an aperitif
LOCATION:Room 1-15, Colloque
TRANSP:TRANSPARENT
CATEGORIES:Colloque
CONTACT:
URL:http://agenda.unige.ch/events/view/36495
FREEBUSY;FBTYPE=FREE:
END:VEVENT
BEGIN:VEVENT
DTSTART:20230525T141500Z
DTEND:20230525T141500Z
DTSTAMP:20240224T185634Z
UID:36496@calendar.unige.ch
CREATED:20230502T154824Z
LAST-MODIFIED:20230504T101517Z
SUMMARY:Random square-tiled surfaces of large genus and random multicurves on surfaces of large genus (Anton Zorich, University Paris Cité)
DESCRIPTION:I will tell how Maxim Kontsevich and Paul Norbury have counted metric ribbon graphs and how Maryam Mirzakhani has counted simple closed geodesic multicurves on hyperbolic surfaces. Both counts use Witten-Kontsevich correlators (they will be defined in the lecture with no appeals to quantum gravity).\n\nI will present a formula for the asymptotic count of square-tiled surfaces of any fixed genus g tiled with at most N squares as N tends to infinity. This count allows, in particular, to compute Masur-Veech volumes of the moduli spaces of quadratic differentials. A deep large genus asymptotic analysis of this formula, performed by Amol Aggarwal, and the uniform large genus asymptotics of intersection numbers of Witten Kontsevich correlators, proved by Aggarwal, combined with the results of Kontsevich, Norbury and Mirzakhani, allowed us to describe the structure of a random multi-geodesic on a hyperbolic surface of large genus and of a random square-tiled surface of large genus.\n\nIf time permits, I will count oriented meanders on surfaces of any genus and an asymptotic probability to get a meander by a random identification of endpoints of a random braid on a two-component surface of any genus. (joint work with V. Delecroix, E. Goujard and P. Zograf)\n\nP.S. The Colloquium will be followed by an aperitif
LOCATION:Room 1-15, Colloque
TRANSP:TRANSPARENT
CATEGORIES:Colloque
CONTACT:
URL:http://agenda.unige.ch/events/view/36496
FREEBUSY;FBTYPE=FREE:
END:VEVENT
BEGIN:VEVENT
DTSTART:20231019T141500Z
DTEND:20231019T141500Z
DTSTAMP:20240224T185634Z
UID:37731@calendar.unige.ch
CREATED:20231016T082133Z
LAST-MODIFIED:20231016T090313Z
SUMMARY:"Graph complexes, homology of the general linear group, and numbers" (Francis Brown, University of Oxford)
DESCRIPTION:This talk will be a guided tour of some very distinct, but highly interconnected areas of combinatorics, algebraic geometry and number theory. Graph complexes were introduced by Kontsevich and encode the contraction of edges in a graph. Despite the elementary definition, their homology is surprisingly complicated and mostly unknown. After surveying recent results in this area, I will turn to the homology of the special linear group, and discuss the classical work of Minkowski on values of the zeta function, Voronoi on quadratic forms, and of Borel on stable cohomology.\nIn the final part of the talk I will try to draw the different strands together, and explain how these topics all share a common underlying pattern.
LOCATION:Room 1-15, Colloque de mathématiques
TRANSP:TRANSPARENT
CATEGORIES:Colloque
CONTACT:
URL:http://agenda.unige.ch/events/view/37731
FREEBUSY;FBTYPE=FREE:
END:VEVENT
BEGIN:VEVENT
DTSTART:20231102T151500Z
DTEND:20231102T151500Z
DTSTAMP:20240224T185634Z
UID:37830@calendar.unige.ch
CREATED:20231025T073207Z
LAST-MODIFIED:20231025T073543Z
SUMMARY:"Irreducibility of random polynomials" (Gady KOZMA, Weizmann Institute of Science)
DESCRIPTION:Take a polynomial of degree n with coefficients +/-1 taken randomly, independently. What is the probability that it is irreducible over the rationals? This question is still open, but a lot of progress happened around it in recent years. We will survey some of this progress, including joint work with Lior Bary-Soroker, Dimitris Koukoulopoulos and David Hokken.\nIn the final part of the talk I will try to draw the different strands together, and explain how these topics all share a common underlying pattern.\n\nThe Colloquium will by followed by an aperitif
LOCATION:Room 1-15, Colloque de mathématiques
TRANSP:TRANSPARENT
CATEGORIES:Colloque
CONTACT:
URL:http://agenda.unige.ch/events/view/37830
FREEBUSY;FBTYPE=FREE:
END:VEVENT
BEGIN:VEVENT
DTSTART:20240215T151500Z
DTEND:20240215T151500Z
DTSTAMP:20240224T185634Z
UID:38795@calendar.unige.ch
CREATED:20240202T153731Z
LAST-MODIFIED:20240202T153731Z
SUMMARY:"Some new geometric ideas in the spectral analysis of Eisenstein series" (Andrei Okounkov, Columbia University)
DESCRIPTION:Eisenstein series constitute an important direct summand of the whole space of automorphic functions, whose role may be compared to scattering states for a quantum many-body system. It is a fundamental problem in the theory of automorphic forms to determine the L^2 spectrum of Laplace and Hecke operators, and for the Eisenstein series this problem has been traditionally approached by methods that are very similar to contour integrals of the resolvent. In a joint work with David Kazhdan, we propose an alternative set of methods, the essence and advantages of which will be discussed in this talk.\nThe Colloquium will by followed by an aperitif.
LOCATION:Room 1-15, Colloque de mathématiques
TRANSP:TRANSPARENT
CATEGORIES:Colloque
CONTACT:
URL:http://agenda.unige.ch/events/view/38795
FREEBUSY;FBTYPE=FREE:
END:VEVENT
BEGIN:VEVENT
DTSTART:20240222T151500Z
DTEND:20240222T151500Z
DTSTAMP:20240224T185634Z
UID:38647@calendar.unige.ch
CREATED:20240129T094411Z
LAST-MODIFIED:20240129T094411Z
SUMMARY:"Geometric representations of Artin groups" (Luis Paris, Université de Bourgogne)
DESCRIPTION:We are interested in the interaction between two families of groups: on the one hand, that of mapping class groups, and, on the other hand, that of simply laced Artin groups. The \emph{mapping class group} of a compact oriented surface, $\Sigma$, denoted by $\MM (\Sigma)$, is the group of isotopy classes of homeomorphisms of $\Sigma$ which preserve the orientation. A \emph{simply laced Artin group} is a group defined by relations of the form $x y = y x$ and $x y x = y x y$. The aim of the talk is to explain how to construct homomorphisms from simply laced Artin groups to mapping class groups, and to explain their usefulness.\n\nThe Colloquium will by followed by an aperitif.
LOCATION:Room 1-15, Colloque de mathématiques
TRANSP:TRANSPARENT
CATEGORIES:Colloque
CONTACT:
URL:http://agenda.unige.ch/events/view/38647
FREEBUSY;FBTYPE=FREE:
END:VEVENT
END:VCALENDAR