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We show that for any degree $d$ hypersurface $Y \subset X$ in a possibly singular projective variety $X \subset \mathbf{P}^N$, the total Betti number of $Y$ is bounded by $3\text{deg}(X)\cdot d^n + C\cdot d^{n-1}$ for some explicit constant…

Algebraic Geometry · Mathematics 2026-01-29 Xuanyu Pan , Dingxin Zhang , Xiping Zhang

We show the existence of a complete, strictly locally convex hypersurface within $\mathbb{H}^{n+1}$ that adheres to a curvature equation applicable to a broad range of curvature functions. This hypersurface possesses a prescribed asymptotic…

Differential Geometry · Mathematics 2023-08-30 Han Hong , Haizhong Li , Meng Zhang

Let $X$ be a hypersurface in $\mathbb{P}^N$ with $N\geq 3$ defined over a finite field. The main result of this note is the classification, up to projective equivalence, of hypersurfaces $X$ as above without a linear component when the…

Algebraic Geometry · Mathematics 2016-04-19 Andrea Luigi Tironi

We show that the existence of an embedded compact, boundaryless hypersurface S of strictly positive mean curvature in a noncompact, connected, complete Riemannian n-manifold N of nonnegative Ricci curvature implies that the homomorphism…

Differential Geometry · Mathematics 2010-12-07 I. P. Costa e Silva

As a generalization of vertex connectivity, for connected graphs $G$ and $T$, the $T$-structure connectivity $\kappa(G, T)$ (resp. $T$-substructure connectivity $\kappa^{s}(G, T)$) of $G$ is the minimum cardinality of a set of subgraphs $F$…

Combinatorics · Mathematics 2022-11-23 Lina Ba , Heping Zhang

Let $\mathbb{S}_h$ denote a sphere with $h$ holes. Given a triangulation $G$ of a surface $\mathbb{M}$, we consider the question of when $G$ contains a spanning subgraph $H$ such that $H$ is a triangulated $\mathbb{S}_h$. We give a new…

Several papers have been written studying unexpected hypersurfaces. We say a finite set of points Z admits unexpected hypersurfaces if a general union of fat linear subspaces imposes less that the expected number of conditions on the ideal…

Algebraic Geometry · Mathematics 2020-03-06 Bill Trok

Atiyah's formulation of what is nowadays called the convexity theorem of Atiyah-Guillemin-Sternberg has two parts: (a) the image of the moment map arising from a Hamiltonian action of a torus on a symplectic manifold is a convex polytope,…

Differential Geometry · Mathematics 2007-05-23 Augustin-Liviu Mare

Let W be a projective variety of dimension n+1, L a free line bundle on W, X in $H^0(L^d)$ a hypersurface of degree d which is generic among those given by sums of monomials from $L$, and let $f : Y \to X$ be a generically finite map from a…

Algebraic Geometry · Mathematics 2007-05-23 L. Chiantini , A. F. Lopez , Z. Ran

Locally convex compact immersed hypersurfaces in Finsler-Hadamard manifolds with bounded T-curvature are considered. We prove that such hypersurfaces are embedded as the boundary of convex body under certain conditions on the normal…

Differential Geometry · Mathematics 2011-10-11 Alexandr A. Borisenko , Eugeny A. Olin

The paper is a contribution to the conjecture of Kobayashi that the complement of a generic curve in the projective plane is hyperbolic, provided the degree is at least five. Previously the authors treated the cases of two quadrics and a…

alg-geom · Mathematics 2014-12-01 Gerd Dethloff , Georg Schumacher , Pit-Mann Wong

Let T be a triangulation of S^3 containing a link L in its 1-skeleton. We give an explicit lower bound for the number of tetrahedra of T in terms of the bridge number of L. Our proof is based on the theory of almost normal surfaces.

Geometric Topology · Mathematics 2014-11-11 Simon A King

Ropelength, L, is a parameter characterizing the minimum contour length of a knot or link. There exist upper and lower bounds on ropelength with respect to crossing number, C, including a universal lower bound constraining $L\geq\alpha_0…

Geometric Topology · Mathematics 2026-03-16 Alexander R. Klotz

We prove the existence of solutions to the asymptotic Plateau problem for hypersurfaces of prescribed mean curvature in Cartan-Hadamard manifolds $N$. More precisely, given a suitable subset $L$ of the asymptotic boundary of $N$ and a…

Differential Geometry · Mathematics 2023-04-03 Jean-Baptiste Casteras , Ilkka Holopainen , Jaime B. Ripoll

A set cover of a hypergraph $H$ is a set of vertices intersecting every hyperedge. In the minimum sum set cover problem, vertices are selected one by one; each edge pays the position of the first vertex that hits it, and the objective is to…

Discrete Mathematics · Computer Science 2026-05-22 Zhongyi Zhang , Yixin Cao

In this paper we investigate the intersection problem for $1$-surfaces immersed in a complete Riemannian three-manifold $P$ with Ricci curvature bounded from below by $-2$. We first prove a Frankel's type theorem for $1$-surfaces with…

Differential Geometry · Mathematics 2022-02-10 G. Pacelli Bessa , Tiarlos Cruz , Leandro F. Pessoa

A joint of a set of lines $\mathcal{L}$ in $\mathbb{F}^d$ is a point that is contained in $d$ lines with linearly independent directions. The joints problem asks for the maximum number of joints that are formed by $L$ lines. Guth and Katz…

Combinatorics · Mathematics 2023-12-25 Ting-Wei Chao , Hung-Hsun Hans Yu

We study the existence and construction of sparse supports for hypergraphs derived from subgraphs of a graph $G$. For a hypergraph $(X,\mathcal{H})$, a support $Q$ is a graph on $X$ s.t. $Q[H]$, the graph induced on vertices in $H$ is…

Combinatorics · Mathematics 2025-06-10 Rajiv Raman , Karamjeet Singh

Given a projective algebraic set X, its dual graph G(X) is the graph whose vertices are the irreducible components of X and whose edges connect components that intersect in codimension one. Hartshorne's connectedness theorem says that if…

Commutative Algebra · Mathematics 2022-08-25 Bruno Benedetti , Matteo Varbaro

A temporal (directed) graph is a graph whose edges are available only at specific times during its lifetime, $\tau$. Paths are sequences of adjacent edges whose appearing times are either strictly increasing or non-strictly increasingly…

Combinatorics · Mathematics 2023-03-01 Isnard Lopes Costa , Raul Lopes , Andrea Marino , Ana Silva