BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Laboratoire de Mathématiques de Versailles - ECPv6.3.5//NONSGML v1.0//EN CALSCALE:GREGORIAN METHOD:PUBLISH X-WR-CALNAME:Laboratoire de Mathématiques de Versailles X-ORIGINAL-URL:https://lmv.math.cnrs.fr X-WR-CALDESC:évènements pour Laboratoire de Mathématiques de Versailles REFRESH-INTERVAL;VALUE=DURATION:PT1H X-Robots-Tag:noindex X-PUBLISHED-TTL:PT1H BEGIN:VTIMEZONE TZID:Europe/Paris BEGIN:DAYLIGHT TZOFFSETFROM:+0100 TZOFFSETTO:+0200 TZNAME:CEST DTSTART:20220327T010000 END:DAYLIGHT BEGIN:STANDARD TZOFFSETFROM:+0200 TZOFFSETTO:+0100 TZNAME:CET DTSTART:20221030T010000 END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTART;TZID=Europe/Paris:20221206T113000 DTEND;TZID=Europe/Paris:20221206T123000 DTSTAMP:20240329T031634 CREATED:20221109T152010Z LAST-MODIFIED:20221208T162240Z UID:11047-1670326200-1670329800@lmv.math.cnrs.fr SUMMARY:PS : Alice le Brigant (Univ. Paris 1) : Fisher information geometry of Dirichlet distributions DESCRIPTION:The Fisher information can be used to define a Riemannian metric to compare probability distributions inside a parametric family. The most well-known example is the case of (univariate) normal distributions\, where the Fisher information induces hyperbolic geometry. In this talk we will investigate the Fisher information geometry of Dirichlet distributions\, and beta distributions as a particular case. We show that it is negatively curved and geodesically complete. This guarantees the uniqueness of the notion of mean distribution\, and makes it a suitable geometry to apply the K-means algorithm\, e.g. to compare and classify histograms. URL:https://lmv.math.cnrs.fr/evenenement/ps-alice-le-brigant-univ-paris-1-fisher-information-geometry-of-dirichlet-distributions/ LOCATION:Bâtiment Fermat\, salle 4205 CATEGORIES:Séminaire PS END:VEVENT BEGIN:VEVENT DTSTART;TZID=Europe/Paris:20221206T133000 DTEND;TZID=Europe/Paris:20221206T143000 DTSTAMP:20240329T031634 CREATED:20221004T075751Z LAST-MODIFIED:20221208T162247Z UID:10865-1670333400-1670337000@lmv.math.cnrs.fr SUMMARY:AG : Carolina Araujo (IMPA\, Brésil) : « Birational geometry of Calabi-Yau pairs » DESCRIPTION:Abstract: Consider the following problem\, originally posed by Gizatullin: « Which automorphisms of a smooth quartic K3 surface in are induced by Cremona transformations of the ambient space? » When S  is a smooth quartic surface in \, the pair (\,S) is an example of a Calabi-Yau pair\, that is\, a mildly singular pair (X\,D) consisting of a normal projective variety X and an effective Weil divisor D on X such that . In this talk\, I will explain a general framework to investigate the birational geometry of Calabi-Yau pairs and how this can be applied to approach Gizatullin’s problem. This is a joint work with Alessio Corti and Alex Massarenti. URL:https://lmv.math.cnrs.fr/evenenement/ag-carolina-araujo-impa-bresil/ LOCATION:Bâtiment Fermat\, salle 4205 CATEGORIES:Séminaire AG END:VEVENT END:VCALENDAR