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Let $A$ be an excellent two-dimensional normal local ring containing an algebraically closed field and let $X\to \mathrm{Spec} (A)$ be a resolution of singularity. We prove a theorem giving a condition under which the dimension of the…

Algebraic Geometry · Mathematics 2025-12-16 Tomohiro Okuma , Kei-ichi Watanabe , Ken-ichi Yoshida

Let $(A, \mathfrak m)$ be a normal two-dimensional local ring and $I$ an $\mathfrak m$-primary integrally closed ideal with a minimal reduction $Q$. Then we calculate the numbers: $\mathrm{nr}(I) = \min\{n \;|\; \overline{I^{n+1}} =…

Commutative Algebra · Mathematics 2025-12-16 Tomohiro Okuma , Kei-ichi Watanabe , Ken-ichi Yoshida

In this paper, we give a formula for normal reduction number of an integrally closed $\mathfrak m$-primary ideal of a $2$-dimensional normal local ring $(A,\mathfrak m)$ in terms of the geometric genus $p_g(A)$ of $A$. Also we compute the…

Commutative Algebra · Mathematics 2025-12-16 Tomohiro Okuma , Kei-ichi Watanabe , Ken-ichi Yoshida

In this work we study some algebraic and topological properties of the ring ${\mathcal O}(X^\nu)$ of global analytic functions of the normalization $(X^\nu,{\mathcal O}_{X^\nu})$ of a reduced complex analytic space $(X,{\mathcal O}_X)$. If…

Algebraic Geometry · Mathematics 2017-10-11 Francesca Acquistapace , Fabrizio Broglia , José F. Fernando

This article consists of two parts. The first part is a survey on the normal reduction numbers of normal surface singularities. It includes results on elliptic singularities, cone-like singularities and homogeneous hypersurface…

Algebraic Geometry · Mathematics 2025-12-16 Tomohiro Okuma

Let $(X,o)$ be a complex normal surface singularity. We fix one of its good resolutions $\widetilde{X}\to X$, an effective cycle $Z$ supported on the reduced exceptional curve, and any possible (first Chern) class $l'\in…

Algebraic Geometry · Mathematics 2018-09-12 János Nagy , András Némethi

We study the analytic and topological invariants associated with complex normal surface singularities. Our goal is to provide topological formulae for several discrete analytic invariants whenever the analytic structure is generic (with…

Algebraic Geometry · Mathematics 2019-09-17 János Nagy , András Némethi

Let $(X,o)$ be a complex normal surface singularity with rational homology sphere link and let $\widetilde{X}$ be one of its good resolutions. Fix an effective cycle $Z$ supported on the exceptional curve and also a possible Chern class…

Algebraic Geometry · Mathematics 2019-09-17 János Nagy , András Némethi

In the present article we work out a relative setup of generic structures on surface singularities. We fix an analytic type on a subgraph of a rational homology sphere resolution graph $\mathcal{T}$ and we choose a relatively generic normal…

Algebraic Geometry · Mathematics 2021-12-30 János Nagy

We introduce the the normal reduction number of two-dimensional normal singularities and prove that elliptic singularity has normal reduction number two. We also prove that for a two-dimensional normal singularity which is not rational, it…

Algebraic Geometry · Mathematics 2025-12-16 Tomohiro Okuma

The so-called Dao numbers are a sort of measure of the asymptotic behaviour of full properties of certain product ideals in a Noetherian local ring $R$ with infinite residue field and positive depth. In this paper, we answer a question of…

Commutative Algebra · Mathematics 2025-01-15 Antonino Ficarra , Cleto B. Miranda-Neto , Douglas S. Queiroz

We fix a complex analytic normal singularity germ $(X,o)$ of dimension $\geq 2$ and a (not necessarily irreducible) reduced Weil divisor $(S,o)\subset (X,o)$. The embedded resolution of the pair determines a multi-index filtration of the…

Algebraic Geometry · Mathematics 2024-05-20 András Némethi , Willem Veys

Let $\mathcal{T}$ be an arbitrary resolution graph and $(X, 0)$ a generic complex analytic normal surface singularity, and $\tilde{X}$ a generic resolution corresponding to it. Fix an effective integer cycle $Z$ supported on the exceptional…

Algebraic Geometry · Mathematics 2020-03-31 János Nagy

Let (C,0) be a reduced curve germ in a normal surface singularity (X,0). The main goal is to recover the delta invariant of the abstract curve (C,0) from the topology of the embedding. We give explicit formulae whenever (C,0) is minimal…

Algebraic Geometry · Mathematics 2020-05-21 José Ignacio Cogolludo-Agustín , Tamás László , Jorge Martín-Morales , András Némethi

Using vanishing of graded components of local cohomology modules of the Rees algebra of the normal filtration of an ideal, we give bounds on the normal reduction number. This helps to get necessary and sufficient conditions in…

Commutative Algebra · Mathematics 2019-10-09 Kriti Goel , Vivek Mukundan , J. K. Verma

In \cite{R} the author investigated invariants of relatively generic structures on surface singularities generalising results of \cite{NNA1} and \cite{NNA2} about generic analytic structures and generic line bundles to the case of the…

Algebraic Geometry · Mathematics 2019-11-27 János Nagy

We explicitly bound T-singularities on normal projective surfaces $W$ with one singularity, and $K_W$ ample. This bound depends only on $K_W^2$, and it is optimal when $W$ is not rational. We classify and realize surfaces attaining the…

Algebraic Geometry · Mathematics 2020-01-28 Julie Rana , Giancarlo Urzúa

If $(\widetilde{X},E)\to (X,o)$ is the resolution of a complex normal surface singularity and $c_1:{\rm Pic}(\widetilde{X})\to H^2(\widetilde{X},{\mathbb Z})$ is the Chern class map, then ${\rm Pic}^{l'}(\widetilde{X}):= c_1^{-1}(l')$ has a…

Algebraic Geometry · Mathematics 2019-02-21 János Nagy , András Némethi

We prove the "End Curve Theorem," which states that a normal surface singularity $(X,o)$ with rational homology sphere link $\Sigma$ is a splice-quotient singularity if and only if it has an end curve function for each leaf of a good…

Algebraic Geometry · Mathematics 2011-07-29 Walter D Neumann , Jonathan Wahl

If $G$ is a complex simply connected semisimple algebraic group and if $\lambda$ is a dominant weight, we consider the compactification $X_\lambda$ in the projectivisation of $\End(V(\lambda))$ obtained as the closure of the $G\times…

Algebraic Geometry · Mathematics 2018-06-26 Paolo Bravi , Jacopo Gandini , Andrea Maffei , Alessandro Ruzzi
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