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The Euler characteristic of a very affine variety encodes the number of critical points of the likelihood equation on this variety. In this paper, we study the Euler characteristic of the complement of a hypersurface arrangement with…

Algebraic Geometry · Mathematics 2024-12-31 Bernhard Reinke , Kexin Wang

We prove a conjecture of Toponogov on complete convex planes, namely that such planes must contain an umbilic point, albeit at infinity. Our proof is indirect. It uses Fredholm regularity of an associated Riemann-Hilbert boundary value…

Differential Geometry · Mathematics 2024-10-01 Brendan Guilfoyle , Wilhelm Klingenberg

We show that measures of irrationality on very general codimension two complete intersections and very general complete intersection surfaces are multiplicative in the degrees of the defining equations. This confirms some cases of a…

Algebraic Geometry · Mathematics 2021-11-11 Nathan Chen

In the recent articles by Alper, Eastwood and Isaev, it was conjectured that all rational $GL_n({\mathbb C})$-invariant functions of forms of degree $d\ge 3$ on ${\mathbb C}^n$ can be extracted, in a canonical way, from those of forms of…

Algebraic Geometry · Mathematics 2016-02-03 Jarod Alper , Alexander Isaev

We prove that for any germ of complex analytic set in $\CC^n$ there exists a hypersurface singularity whose Milnor fibration has trivial geometric monodromy and fibre homotopic to the complement of the germ of complex analytic set. As an…

Algebraic Geometry · Mathematics 2011-02-17 Javier Fernandez de Bobadilla

Let $Q$ be a quiver with dimension vector $\alpha$ prehomogeneous under the action of the product of general linear groups $\operatorname{GL}(\alpha)$ on the representation variety $\operatorname{Rep}(Q,\alpha)$. We study geometric…

Representation Theory · Mathematics 2017-07-05 András Cristian Lőrincz

In this sequence, we first prove an abstract Morse index theorem in a Hilbert space modeling a variational problem with constraints. Then, our abstract formulation is applied to study several optimization setups including closed CMC…

Differential Geometry · Mathematics 2026-01-23 Hung Tran , Detang Zhou

We prove the "Sullivan Conjecture" on the classification of 4-dimensional complete intersections up to diffeomorphism. Here an $n$-dimensional complete intersection is a smooth complex variety formed by the transverse intersection of $k$…

Geometric Topology · Mathematics 2025-02-11 Diarmuid Crowley , Csaba Nagy

We propose a geometric and categorical approach to the Hodge Conjecture for all smooth projective complex varieties. By embedding any such variety into a flat family with general fibers smooth complete intersections, we prove the conjecture…

Algebraic Geometry · Mathematics 2025-08-15 Karim Mansour

Let S $\subseteq$ N be a numerical semigroup with multiplicity m = min(S \ {0}) and conductor c = max(N \ S) + 1. Let P be the set of primitive elements of S, and let L be the set of elements of S which are smaller than c. A longstand-ing…

Combinatorics · Mathematics 2021-08-19 Shalom Eliahou

We define strict and weak duality involutions on 2-categories, and prove a coherence theorem that every bicategory with a weak duality involution is biequivalent to a 2-category with a strict duality involution. For this purpose we…

Category Theory · Mathematics 2018-01-26 Michael Shulman

We prove a general likely intersections theorem, a counterpart to the Zilber-Pink conjectures, under the assumption that the Ax-Schanuel property and some mild additional conditions are known to hold for a given category of complex quotient…

Algebraic Geometry · Mathematics 2026-01-14 Sebastian Eterović , Thomas Scanlon

We give a recursive formula, expressed in terms of the characteristic tuples, for the Betti numbers of the boundary of the Milnor fiber of an irreducible quasi-ordinary surface. The singular locus of the surface consists of two components,…

Algebraic Geometry · Mathematics 2019-06-18 Gary Kennedy , Lee McEwan

A classical argument was introduced by Khintchine in 1926 in order to exhibit the existence of totally irrational singular linear forms in two variables. This argument was subsequently revisited and extended by many authors. For instance,…

Number Theory · Mathematics 2026-01-14 Dmitry Kleinbock , Nikolay Moshchevitin , Jacqueline Warren , Barak Weiss

We prove a conjecture of Teissier asserting that if $f$ has an isolated singularity at $P$ and $H$ is a smooth hypersurface through $P$, then $\widetilde{\alpha}_P(f)\geq \widetilde{\alpha}_P(f\vert_H)+\frac{1}{\theta_P(f)+1}$, where…

Algebraic Geometry · Mathematics 2021-12-24 Bradley Dirks , Mircea Mustata

The image of a finitely determined holomorphic germ $\Phi$ from $\mathbb{C}^2$ to $\mathbb{C}^3$ defines a hypersurface singularity $(X,0)$, which is in general non-isolated. We show that the diffeomorphism type of the boundary of the…

Geometric Topology · Mathematics 2025-05-02 Gergő Pintér , Tamás Terpai

Recently Wolff obtained a nearly sharp $L^2$ bilinear restriction theorem for bounded subsets of the cone in general dimension. We obtain the endpoint of Wolff's estimate and generalize to the case when one of the subsets is large. As a…

Classical Analysis and ODEs · Mathematics 2007-05-23 Terence Tao

It was shown by Kuznetsov that complete intersections of $n$ generic quadrics in ${\mathbb P}^{2n-1}$ are related by Homological Projective Duality to certain non-commutative (Clifford) varieties which are in some sense birational to double…

Algebraic Geometry · Mathematics 2018-05-18 Lev Borisov , Chengxi Wang

Let $f : X\to \Delta$ be a $1$-parameter family of $2$-dimensional isolated hypersurface singularities. In this paper, we show that if the Milnor number is constant, then any semistable model, obtained from $f$ after a sufficiently large…

Algebraic Geometry · Mathematics 2023-12-05 Marta Aldasoro Rosales

Comparison theorems are foundational to our understanding of the geometric features implied by various curvature constraints. This paper considers manifolds with a positive lower bound on either scalar, 2-Ricci, or Ricci curvature, and…

Differential Geometry · Mathematics 2023-05-29 Sven Hirsch , Demetre Kazaras , Marcus Khuri , Yiyue Zhang