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We present three families of minimal border rank tensors: they come from highest weight vectors, smoothable algebras, or monomial algebras. We analyse them using Strassen's laser method and obtain an upper bound $2.431$ on $\omega$. We also…

Algebraic Geometry · Mathematics 2022-04-13 Roser Homs , Joachim Jelisiejew , Mateusz Michałek , Tim Seynnaeve

Tensors decompositions are a class of tools for analysing datasets of high dimensionality and variety in a natural manner, with the Canonical Polyadic Decomposition (CPD) being a main pillar. While the notion of CPD is closely intertwined…

Signal Processing · Electrical Eng. & Systems 2019-11-15 Giuseppe G. Calvi , Bruno Scalzo Dees , Danilo P. Mandic

The results of Strassen and Raz show that good enough tensor rank lower bounds have implications for algebraic circuit/formula lower bounds. We explore tensor rank lower and upper bounds, focusing on explicit tensors. For odd d, we…

Computational Complexity · Computer Science 2012-03-05 Boris Alexeev , Michael Forbes , Jacob Tsimerman

Phylogenetic networks are a generalization of evolutionary or phylogenetic trees that are commonly used to represent the evolution of species which cross with one another. A special type of phylogenetic network is an {\em $X$-cactus}, which…

Populations and Evolution · Quantitative Biology 2021-09-08 Andrew Francis , Katharina T. Huber , Vincent Moulton , Taoyang Wu

We show that the Waring rank of the $3 \times 3$ determinant, previously known to be between $14$ and $18$, is at least $15$. We use syzygies of the apolar ideal, which have not been used in this way before. Additionally, we show that the…

Algebraic Geometry · Mathematics 2019-11-11 Mats Boij , Zach Teitler

We study the generic and typical ranks of 3-tensors of dimension l x m x n using results from matrices and algebraic geometry. We state a conjecture about the exact values of the generic rank of 3-tensors over the complex numbers, which is…

Algebraic Geometry · Mathematics 2011-01-25 Shmuel Friedland

We study pushdown vector addition systems, which are synchronized products of pushdown automata with vector addition systems. The question of the boundedness of the reachability set for this model can be refined into two decision problems…

Formal Languages and Automata Theory · Computer Science 2015-07-28 Jérôme Leroux , Grégoire Sutre , Patrick Totzke

We study rank-three matroids, known as point-line configurations, and their associated matroid varieties, defined as the Zariski closures of their realization spaces. Our focus is on determining finite generating sets of defining equations…

Combinatorics · Mathematics 2025-06-10 Emiliano Liwski , Fatemeh Mohammadi , Lisa Vandebrouck

We give non-trivial lower bounds for the border rank of families of $\mathbf{GL}(V)$-invariant tensors in $U\otimes \mathbf{S}_\lambda V\otimes \mathbf{S}_\mu V$ where $U$ is $V$, $\mathrm{Sym}^2V$ or $\bigwedge^2V$. We build on the…

Algebraic Geometry · Mathematics 2025-08-26 Suhas Vadan Gondi

We analyze Kumar's recent quadratic algebraic branching program size lower bound proof method (CCC 2017) for the power sum polynomial. We present a refinement of this method that gives better bounds in some cases. The lower bound relies on…

Computational Complexity · Computer Science 2022-12-27 Fulvio Gesmundo , Purnata Ghosal , Christian Ikenmeyer , Vladimir Lysikov

The number of $n$-gaussoids is shown to be a double exponential function in $n$. The necessary bounds are achieved by studying construction methods for gaussoids that rely on prescribing $3$-minors and encoding the resulting combinatorial…

Combinatorics · Mathematics 2021-10-26 Tobias Boege , Thomas Kahle

A decision tree is commonly restricted to use a single hyperplane to split the covariate space at each of its internal nodes. It often requires a large number of nodes to achieve high accuracy, hurting its interpretability. In this paper,…

Machine Learning · Computer Science 2020-10-23 Mohammadreza Armandpour , Mingyuan Zhou

We derive upper and lower bounds on the determinant of an exponential matrix. They can be transformed into corresponding bounds for the determinant of a univariate Gaussian matrix.

Numerical Analysis · Mathematics 2026-03-23 Michael S. Floater

The determination of the maximal ranks of a set of a given type of tensors is a basic problem both in theory and application. In statistical applications, the maximal rank is related to the number of necessary parameters to be built in a…

Rings and Algebras · Mathematics 2008-08-21 Toshio Sakata , Toshio Sumi , Mitsuhiro Miyazaki

The discriminant of a multivariate polynomial with indeterminate coefficients is not necessarily a hypersurface, and characterizing its codimension was an open problem for quite a while. We resolve this problem for the discriminants of…

Algebraic Geometry · Mathematics 2026-02-17 Vladislav Pokidkin

In this article, we introduce the $k$-th collineation variety of a third order tensor. This is the closure of the image of the rational map of size $k$ minors of a matrix of linear forms associated to the tensor. We classify such varieties…

Algebraic Geometry · Mathematics 2025-01-23 Fulvio Gesmundo , Hanieh Keneshlou

This article studies the Minimum Spanning Tree Problem under Explorable Uncertainty as well as a related vertex uncertainty version of the problem. We particularly consider special instance types, including cactus graphs, for which we…

Data Structures and Algorithms · Computer Science 2022-11-29 Corinna Mathwieser , Eranda Cela

We present the theory of rank-metric codes with respect to the 3-tensors that generate them. We define the generator tensor and the parity check tensor of a matrix code, and describe the properties of a code through these objects. We define…

Information Theory · Computer Science 2019-04-11 Eimear Byrne , Alessandro Neri , Alberto Ravagnani , John Sheekey

An \"{u}bercrossing diagram is a knot diagram with only one crossing that may involve more than two strands of the knot. Such a diagram without any nested loops is called a petal projection. Every knot has a petal projection from which the…

Geometric Topology · Mathematics 2022-08-10 Allison Henrich , Robin Truax

These lecture notes are intended as an introduction to several notions of tensor rank and their connections to the asymptotic complexity of matrix multiplication. The latter is studied with the exponent of matrix multiplication, which will…

Algebraic Geometry · Mathematics 2022-08-01 Giorgio Ottaviani , Philipp Reichenbach