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Related papers: Singular McKay correspondence for normal surfaces

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An old conjecture of Durfee 1978 bounds the ratio of two basic invariants of complex isolated complete intersection surface singularities: the Milnor number and the singularity (or geometric) genus. We give a counterexample for the case of…

Algebraic Geometry · Mathematics 2011-11-08 Dmitry Kerner , András Némethi

Let M be a quasiprojective algebraic manifold with K_M=0 and G a finite automorphism group of M acting trivially on the canonical class K_M; for example, a subgroup G of SL(n,C) acting on C^n in the obvious way. We aim to study the quotient…

Algebraic Geometry · Mathematics 2007-05-23 Miles Reid

We analyze the embedding dimension of a normal weighted homogeneous surface singularity, and more generally, the Poincar\'e series of the minimal set of generators of the graded algebra of regular functions, provided that the link of the…

Algebraic Geometry · Mathematics 2025-12-16 András Némethi , Tomohiro Okuma

We give positivity conditions on the embedding of a smooth variety which guarantee the normality of the secant variety, generalizing earlier results of the author and others. We also give classes of secant varieties satisfying the Hodge…

Algebraic Geometry · Mathematics 2007-12-17 Pete Vermeire

We study the topological triviality and the Whitney equisingularity of a family of isolated determinantal singularities. On one hand, we give a L\^e-Ramanujam type theorem for this kind of singularities by using the vanishing Euler…

Algebraic Geometry · Mathematics 2014-05-15 J. J. Nuño-Ballesteros , B. Oréfice-Okamoto , J. N. Tomazella

We study local, analytic solutions for a class of initial value problems for singular ODEs. We prove existence and uniqueness of such solutions under a certain non-resonance condition. Our proof translates the singular initial value problem…

Dynamical Systems · Mathematics 2021-08-19 Thomas Geert de Jong , Patrick van Meurs

A genus one curve of degree 5 is defined by the 4 x 4 Pfaffians of a 5 x 5 alternating matrix of linear forms on P^4. We describe a general method for investigating the invariant theory of such models. We use it to explain how we found our…

Number Theory · Mathematics 2011-10-18 Tom Fisher

Mather and Yau showed that an isolated complex hypersurface singularity is completely determined by its moduli algebra. It is shown, for the simple elliptic singularities, how to construct continuous invariants from the moduli algebras and,…

Algebraic Geometry · Mathematics 2007-05-23 Michael G. Eastwood

This paper deals with a study of the rational elliptic surfaces whose $J$-invariant functions are of degree one. Almost all of these elliptic surfaces have four singular fibers, while the remaining surfaces have only three singular fibers.…

Algebraic Geometry · Mathematics 2019-09-27 Takashi Kitazawa

We define orbifold elliptic genus for general orbifolds which generalizes the definition of Borisov and Libgober, and prove their rigidity property.

Differential Geometry · Mathematics 2007-05-23 Chongying Dong , Kefeng Liu , Xiaonan Ma

We consider smooth flows preserving a smooth invariant measure, or, equivalently, locally Hamiltonian flows on compact orientable surfaces and show that almost every such locally Hamiltonian flow with only simple saddles has singular…

Dynamical Systems · Mathematics 2025-05-20 Krzysztof Frączek , Adam Kanigowski , Corinna Ulcigrai

We study invariant Seifert surfaces for strongly invertible knots, and prove that the gap between the equivariant genus (the minimum of the genera of invariant Seifert surfaces) of a strongly invertible knot and the (usual) genus of the…

Geometric Topology · Mathematics 2022-08-30 Mikami Hirasawa , Ryota Hiura , Makoto Sakuma

Normally one assumes isolated surface singularities to be normal. The purpose of this paper is to show that it can be useful to look at nonnormal singularities. By deforming them interesting normal singularities can be constructed, such as…

Algebraic Geometry · Mathematics 2015-12-14 Jan Stevens

Let $M^n$ be either a simply connected space form or a rank-one symmetric space of noncompact type. We consider Weingarten hypersurfaces of $M\times\mathbb R$, which are those whose principal curvatures $k_1,\dots ,k_n$ and angle function…

Differential Geometry · Mathematics 2022-12-09 Ronaldo F. de Lima , Álvaro K. Ramos , João P. dos Santos

We define a generalization of convex functions, which we call $\delta$-convex functions, and show they must satisfy interior H\"older and $W^{1,p}$ estimates. As an application, we consider solutions of a certain class of fully nonlinear…

Differential Geometry · Mathematics 2007-05-23 Matthew Gursky , Jeff Viaclovsky

In the present article we determine and characterize completely the support genus, the binding number and the norm of a page of an open book under the following restrictions: M is a rational homology sphere which can be realized as the link…

Algebraic Geometry · Mathematics 2009-08-31 A. Nemethi , M. Tosun

This paper concerns spectral invariants of the Laplacian on a compact Riemannian manifold (M,g) known as wave invariants. If U(t) denotes the wave group of (M,g), then the trace Tr U(t) is singular when t = 0 or when ti is the length of a…

Spectral Theory · Mathematics 2007-05-23 Steve Zelditch

Let G be a polyhedral group, namely a finite subgroup of SO(3). Nakamura's G-Hilbert scheme provides a preferred Calabi-Yau resolution Y of the polyhedral singularity C^3/G. The classical McKay correspondence describes the classical…

Algebraic Geometry · Mathematics 2015-05-13 Jim Bryan , Amin Gholampour

In this paper we generalize Artin-Verdier, Esnault and Wunram construction of McKay correspondence to arbitrary Gorenstein surface singularities. The key idea is the definition and a systematic use of a degeneracy module, which is an…

Algebraic Geometry · Mathematics 2019-04-05 Javier Fernandez de Bobadilla , Agustin Romano Velazquez

This paper continues our researches \cite{DS1, DS2, DS3} by computing some invariants based on Hilbert-Poincar\'{e} series associated to Milnor algebras. Our computations are for some of the classical surfaces and 3-folds with different…

Algebraic Geometry · Mathematics 2013-10-01 Gabriel Sticlaru
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