4,257 research outputs found

    Upsilon invariants from cyclic branched covers

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    We extend the construction of upsilon-type invariants to null-homologous knots in rational homology three-spheres. By considering mm-fold cyclic branched covers with mm a prime power, this extension provides new knot concordance invariants ΥmC(K)\Upsilon_m^C (K). We give computations of these invariants for some families of alternating knots and reprove some independence results.Comment: 26 pages, 13 figures. Comments are welcome

    Towards a theory of local Shimura varieties

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    This is a survey article that advertizes the idea that there should exist a theory of p-adic local analogues of Shimura varieties. Prime examples are the towers of rigid-analytic spaces defined by Rapoport-Zink spaces, and we also review their theory in the light of this idea. We also discuss conjectures on the â„“\ell-adic cohomology of local Shimura varieties.Comment: 53 page

    Smashing localizations of rings of weak global dimension at most one

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    We show for a ring R of weak global dimension at most one that there is a bijection between the smashing subcategories of its derived category and the equivalence classes of homological epimorphisms starting in R. If, moreover, R is commutative, we prove that the compactly generated localizing subcategories correspond precisely to flat epimorphisms. We also classify smashing localizations of the derived category of any valuation domain, and provide an easy criterion for the Telescope Conjecture (TC) for any commutative ring of weak global dimension at most one. As a consequence, we show that the TC holds for any commutative von Neumann regular ring R, and it holds precisely for those Pr\"ufer domains which are strongly discrete.Comment: 45 pages; version 2: several changes in the presentation (a section on the homotopy category of dg algebras became an appendix, more explanation added at various places of the text), main results unchange
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