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Related papers: Distinguishing secant from cactus varieties

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Models like support vector machines or Gaussian process regression often require positive semi-definite kernels. These kernels may be based on distance functions. While definiteness is proven for common distances and kernels, a proof for a…

Machine Learning · Computer Science 2018-07-11 Martin Zaefferer , Thomas Bartz-Beielstein , Günter Rudolph

The secant method, as an important approach for solving nonlinear equations, is introduced in nearly all numerical analysis textbooks. However, most textbooks only briefly address the Q-order of convergence of this method, with few…

Numerical Analysis · Mathematics 2025-10-16 Yan Tan , Chenhao Ye , Qinghai Zhang , Shubo Zhao

The Green-Lazarsfeld Secant Conjecture is a generalization of Green's Conjecture on syzygies of canonical curves to the cases of arbitrary line bundles. We establish the Green-Lazarsfeld Secant Conjecture for curves of genus g in all the…

Algebraic Geometry · Mathematics 2026-05-27 Gavril Farkas

As is well known, the "usual discrepancy" is defined for a normal Q-Gorenstein variety. By using this discrepancy we can define a canonical singularity and a log canonical singularity. In the same way, by using a new notion, Mather-Jacobian…

Algebraic Geometry · Mathematics 2013-10-28 Lawrence Ein , Shihoko Ishii

We give a quasi-isometric characterization of cacti, which is similar to Manning's characterization of quasi-trees by the bottleneck property. We also give another quasi-isometric characterization of cacti using fat theta curves.

Metric Geometry · Mathematics 2023-05-16 Koji Fujiwara , Panos Papasoglu

For a collection $\mathcal{F}$ of graphs, the $\mathcal{F}$-\textsc{Contraction} problem takes a graph $G$ and an integer $k$ as input and decides if $G$ can be modified to some graph in $\mathcal{F}$ using at most $k$ edge contractions.…

Data Structures and Algorithms · Computer Science 2025-05-21 R. Krithika , Pranabendu Misra , Prafullkumar Tale

Automatic identification of plant specimens from amateur photographs could improve species range maps, thus supporting ecosystems research as well as conservation efforts. However, classifying plant specimens based on image data alone is…

Computer Vision and Pattern Recognition · Computer Science 2021-10-06 Riccardo de Lutio , Yihang She , Stefano D'Aronco , Stefania Russo , Philipp Brun , Jan D. Wegner , Konrad Schindler

We study the problem of characterizing linear preserver subgroups of algebraic varieties, with a particular emphasis on secant varieties and other varieties of tensors. We introduce a number of techniques built on different geometric…

Algebraic Geometry · Mathematics 2025-04-17 Fulvio Gesmundo , Young In Han , Benjamin Lovitz

A cactus graph is a graph in which any two cycles are edge-disjoint. We present a constructive proof of the fact that any plane graph $G$ contains a cactus subgraph $C$ where $C$ contains at least a $\frac{1}{6}$ fraction of the triangular…

Discrete Mathematics · Computer Science 2019-03-18 Parinya Chalermsook , Andreas Schmid , Sumedha Uniyal

Vine copula models have become highly popular and practical tools for modelling multivariate probability distributions due to their flexibility in modelling different kinds of dependences between the random variables involved. However,…

Methodology · Statistics 2025-12-17 Dániel Pfeifer , Edith Alice Kovács

In the Telephone Broadcasting problem, the goal is to disseminate a message from a given source vertex of an input graph to all other vertices in the minimum number of rounds, where at each round, an informed vertex can send the message to…

Data Structures and Algorithms · Computer Science 2025-02-12 Aida Aminian , Shahin Kamali , Seyed-Mohammad Seyed-Javadi , Sumedha

Regular vine copulas can describe a wider array of dependency patterns than the multivariate Gaussian copula or the multivariate Student's t copula. This paper presents two contributions related to model selection of regular vine copulas.…

Statistics Theory · Mathematics 2015-12-04 Lutz Gruber , Claudia Czado

High-quality instance segmentation has shown emerging importance in computer vision. Without any refinement, DCT-Mask directly generates high-resolution masks by compressed vectors. To further refine masks obtained by compressed vectors, we…

Computer Vision and Pattern Recognition · Computer Science 2023-02-08 Qinrou Wen , Jirui Yang , Xue Yang , Kewei Liang

Fine-grained visual classification (FGVC) requires distinguishing between visually similar categories through subtle, localized features - a task that remains challenging due to high intra-class variability and limited inter-class…

Computer Vision and Pattern Recognition · Computer Science 2025-09-22 Johann Schmidt , Sebastian Stober , Joachim Denzler , Paul Bodesheim

Non-classical virtual knots may have non-isomorphic upper and lower quandles. We exploit this property to define the quandle difference invariant, which can detect non-classicality by comparing the numbers of homomorphisms into a finite…

Geometric Topology · Mathematics 2007-05-23 Natasha Harrell , Sam Nelson

Motivated by string topology and the arc operad, we introduce the notion of quasi-operads and consider four (quasi)-operads which are different varieties of the operad of cacti. These are cacti without local zeros (or spines) and cacti…

Quantum Algebra · Mathematics 2014-10-01 Ralph M. Kaufmann

In this paper, we consider different constrained partition problems for weighted trees and cactus graphs. We focus on the (l,u)-partition problem, which is the problem of partitioning a weighted graph into connected clusters such that each…

Data Structures and Algorithms · Computer Science 2022-03-03 Maike Buchin , Leonie Selbach

It is proved that the chordal variety of the Veronese variety v_d(P^n) is projectively normal, arithmetically Cohen-Macaulay and its homogeneous ideal is generated by the 3 x 3 minors of two catalecticant matrices. These results are…

Algebraic Geometry · Mathematics 2007-05-23 Vassil Kanev

The aim of this paper is to provide another perspective on secant varieties on algebraic curves by reformulating the problem in terms of refined de Jonqui\`eres divisors, that is divisors on the curve with prescribed multiplicities and…

Algebraic Geometry · Mathematics 2019-12-17 Mara Ungureanu

We prove that the generic element of the fifth secant variety $\sigma_5(Gr(\mathbb{P}^2,\mathbb{P}^9)) \subset \mathbb{P}(\bigwedge^3 \mathbb{C}^{10})$ of the Grassmannian of planes of $\mathbb{P}^9$ has exactly two decompositions as a sum…

Algebraic Geometry · Mathematics 2018-02-19 Davide Vanzo , Alessandra Bernardi