-
作者：Casagrande, C.
作者单位：University of Turin
摘要：Let X be a smooth, complex Fano 4-fold, and rho(X) its Picard number. We show that if rho(X) > 12, then X is a product of del Pezzo surfaces. The proof relies on a careful study of divisorial elementary contractions f : X -> Y such that dim f (Exc(f)) = 2, together with the author's previous work on Fano 4-folds. In particular, given f : X -> Y as above, under suitable assumptions we show that S := f(Exc(f)) is a smooth del Pezzo surface with -K-S = (-K-Y)(|S).
-
作者：Chatham, Hood; Hahn, Jeremy; Yuan, Allen
作者单位：Massachusetts Institute of Technology (MIT)
摘要：We construct a canonical family of even periodic E infinity\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathbb{E}_{\infty}$\end{document}-ring spectra, with exactly one member of the family for every prime p\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{...
-
作者：Bordenave, Charles; Collins, Benoit
作者单位：Aix-Marseille Universite; Centre National de la Recherche Scientifique (CNRS); Aix-Marseille Universite; Kyoto University
摘要：Voiculescu discovered asymptotic freeness of independent Haar-distributed unitary matrices. Many refinements have been obtained, including strong asymptotic freeness of random unitaries and strong asymptotic freeness of random permutations acting on the orthogonal of the Perron-Frobenius eigenvector. In this paper, we consider a new matrix unitary model appearing naturally from representation theory of compact groups. We fix a nontrivial signature rho\documentclass[12pt]{minimal} \usepackage{a...
-
作者：Liu, Yuan; Wood, Melanie Matchett; Zureick-Brown, David
作者单位：University of Illinois System; University of Illinois Urbana-Champaign; Harvard University; Amherst College
摘要：We consider the distribution of the Galois groups Gal(Kun/K)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\operatorname {Gal}(K<^>{\operatorname{un}}/K)$\end{document} of maximal unramified extensions as K\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amss...
-
作者：Drivas, Theodore D.; Elgindi, Tarek M.; Jeong, In-Jee
作者单位：State University of New York (SUNY) System; Stony Brook University; Duke University; Seoul National University (SNU); Seoul National University (SNU)
摘要：We introduce a notion of stability for non-autonomous Hamiltonian flows on two-dimensional annular surfaces. This notion of stability is designed to capture the sustained twisting of particle trajectories. The main Theorem is applied to establish a number of results that reveal a form of irreversibility in the Euler equations governing the motion of an incompressible and inviscid fluid. In particular, we show that nearby general stable steady states (i) all fluid flows exhibit indefinite twist...
-
作者：Sawin, Will; Wood, Melanie Matchett
作者单位：Princeton University; Harvard University
-
作者：Sawin, Will; Wood, Melanie Matchett
作者单位：Princeton University; Harvard University
摘要：For G\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$G$\end{document} and H1,& mldr;,Hn\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$H...
-
作者：Bao, Huanchen; He, Xuhua
作者单位：National University of Singapore; University of Hong Kong
摘要：The totally nonnegative flag variety was introduced by Lusztig. It has enriched combinatorial, geometric, and Lie-theoretic structures. In this paper, we introduce a (new) J \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$J$\end{document} -total positivity on the full flag variety of an arbitrary Kac-Moody group, ge...
-
作者：Bojko, Arkadij; Lim, Woonam; Moreira, Miguel
作者单位：Swiss Federal Institutes of Technology Domain; ETH Zurich
摘要：In enumerative geometry, Virasoro constraints were first conjectured in Gromov-Witten theory with many new recent developments in the sheaf theoretic context. In this paper, we rephrase the sheaf theoretic Virasoro constraints in terms of primary states coming from a natural conformal vector in Joyce's vertex algebra. This shows that Virasoro constraints are preserved under wall-crossing. As an application, we prove the conjectural Virasoro constraints for moduli spaces of torsion-free sheaves...
-
作者：Guo, Haoyang; Reinecke, Emanuel
作者单位：University of Chicago; Institute for Advanced Study - USA
摘要：Let X\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$X$\end{document} be a smooth p\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$p$\en...
