{"title":"Free Proalgebraic Groups","authors":"M. Wibmer","doi":"10.46298/epiga.2020.volume4.5733","DOIUrl":"https://doi.org/10.46298/epiga.2020.volume4.5733","url":null,"abstract":"Replacing finite groups by linear algebraic groups, we study an\u0000algebraic-geometric counterpart of the theory of free profinite groups. In\u0000particular, we introduce free proalgebraic groups and characterize them in\u0000terms of embedding problems. The main motivation for this endeavor is a\u0000differential analog of a conjecture of Shafarevic.\u0000\u0000 Comment: 36 pages, final accepted version","PeriodicalId":41470,"journal":{"name":"Epijournal de Geometrie Algebrique","volume":"4 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2019-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70483948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The space of twisted cubics","authors":"K. Heinrich, R. Skjelnes, J. Stevens","doi":"10.46298/epiga.2021.volume5.5573","DOIUrl":"https://doi.org/10.46298/epiga.2021.volume5.5573","url":null,"abstract":"We consider the Cohen-Macaulay compactification of the space of twisted\u0000cubics in projective n-space. This compactification is the fine moduli scheme\u0000representing the functor of CM-curves with Hilbert polynomial 3t+1. We show\u0000that the moduli scheme of CM-curves in projective 3-space is isomorphic to the\u0000twisted cubic component of the Hilbert scheme. We also describe the\u0000compactification for twisted cubics in n-space.\u0000\u0000 Comment: 22 pages. Final version","PeriodicalId":41470,"journal":{"name":"Epijournal de Geometrie Algebrique","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70484546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Variation of stable birational types in positive characteristic","authors":"Stefan Schreieder","doi":"10.46298/epiga.2020.volume3.5728","DOIUrl":"https://doi.org/10.46298/epiga.2020.volume3.5728","url":null,"abstract":"Let k be an uncountable algebraically closed field and let Y be a smooth\u0000projective k-variety which does not admit a decomposition of the diagonal. We\u0000prove that Y is not stably birational to a very general hypersurface of any\u0000given degree and dimension. We use this to study the variation of the stable\u0000birational types of Fano hypersurfaces over fields of arbitrary characteristic.\u0000This had been initiated by Shinder, whose method works in characteristic zero.\u0000\u0000 Comment: 14 pages; final version, published in EPIGA","PeriodicalId":41470,"journal":{"name":"Epijournal de Geometrie Algebrique","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2019-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47198007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Refined Verlinde formulas for Hilbert schemes of points and moduli\u0000 spaces of sheaves on K3 surfaces","authors":"L. Gottsche","doi":"10.46298/epiga.2020.volume4.5282","DOIUrl":"https://doi.org/10.46298/epiga.2020.volume4.5282","url":null,"abstract":"We compute generating functions for elliptic genera with values in line\u0000bundles on Hilbert schemes of points on surfaces. As an application we also\u0000compute generating functions for elliptic genera with values in determinant\u0000line bundles on moduli spaces of sheaves on K3 surfaces.\u0000","PeriodicalId":41470,"journal":{"name":"Epijournal de Geometrie Algebrique","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2019-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70483934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}