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Related papers: A Generalized Cross Ratio

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We present a definition of and discuss basic properties of cross-ratios over noncommutative skew-fields. A new theorem was added.

Rings and Algebras · Mathematics 2015-06-18 Vladimir Retakh

This paper introduces advances in the geometry of the transforms for cross ratio of four points in a line in the Desargues affine plane. The results given here have a clean, based Desargues affine plan axiomatic and definitions of addition…

General Mathematics · Mathematics 2025-04-14 Orgest Zaka

We discuss the cross-ratio map of planar quadrilateral linkages, also in the case when one of the links is telescopic. Most of our results are valid for a planar quadrilateral linkage with generic lengths of the sides. In particular, we…

Metric Geometry · Mathematics 2015-08-12 Giorgi Khimshiashvili , Dirk Siersma

Generalization of the cross ratio to polarizations of linear finite and infinite-dimensional spaces (in particular to Sato Grassmannian) is given and explored. This cross ratio appears to be a cocycle of the canonical (tautalogical) bundle…

Analysis of PDEs · Mathematics 2007-05-23 M. I. Zelikin

Tree decompositions of graphs are of fundamental importance in structural and algorithmic graph theory. Planar decompositions generalise tree decompositions by allowing an arbitrary planar graph to index the decomposition. We prove that…

Combinatorics · Mathematics 2007-06-13 David R. Wood , Jan Arne Telle

We consider metric graph Gaussian free field (GFF) defined on polygons of $\delta\mathbb{Z}^2$ with alternating boundary data. The crossing probabilities for level-set percolation of metric graph GFF have scaling limits. When the boundary…

Probability · Mathematics 2020-04-21 Mingchang Liu , Hao Wu

Classical path search assumes complete graphs and scalar optimization metrics, yet real infrastructure networks are incomplete and require multi-dimensional evaluation. We introduce the concept of traversal: a generalization of paths that…

Networking and Internet Architecture · Computer Science 2026-02-24 Nicolas Tacheny

Graphs are commonly used to represent and visualize causal relations. For a small number of variables, this approach provides a succinct and clear view of the scenario at hand. As the number of variables under study increases, the graphical…

Machine Learning · Statistics 2023-08-16 Santtu Tikka , Jouni Helske , Juha Karvanen

The crossing probability in the time direction is defined for an off-equilibrium reaction-diffusion system as the probability that the system of size L is still active at time t, in the finite-size scaling limit. Exact results are obtained…

Statistical Mechanics · Physics 2007-05-23 L. Turban

We present, to the best of the authors' knowledge, all known results for the (planar) crossing numbers of specific graphs and graph families. The results are separated into various categories; specifically, results for general graph…

Combinatorics · Mathematics 2021-12-09 Kieran Clancy , Michael Haythorpe , Alex Newcombe

A $k$-crossing family in a point set $S$ in general position is a set of $k$ segments spanned by points of $S$ such that all $k$ segments mutually cross. In this short note we present two statements on crossing families which are based on…

Computational Geometry · Computer Science 2022-10-03 Oswin Aichholzer , Jan Kynčl , Manfred Scheucher , Birgit Vogtenhuber , Pavel Valtr

We consider the number of crossings in a graph which is embedded randomly on a convex set of points. We give an estimate to the normal distribution in Kolmogorov distance which implies a convergence rate of order $n^{-1/2}$ for various…

Combinatorics · Mathematics 2022-08-26 Santiago Arenas-Velilla , Octavio Arizmendi

We study the algorithmic aspect of edge bundling. A bundled crossing in a drawing of a graph is a group of crossings between two sets of parallel edges. The bundled crossing number is the minimum number of bundled crossings that group all…

Computational Geometry · Computer Science 2016-09-02 Md. Jawaherul Alam , Martin Fink , Sergey Pupyrev

Consider $n$ points distributed uniformly in $[0,1]^d$. Form a graph by connecting two points if their mutual distance is no greater than $r(n)$. This gives a random geometric graph, $\gnrn$, which is connected for appropriate $r(n)$. We…

Probability · Mathematics 2007-05-23 Sanatan Rai

We prove that the number of crossings in a random labelled tree with vertices in convex position is asymptotically Gaussian with mean $ n^2/6$ and variance $ n^3/45$. A similar result is proved for points in general position under mild…

Probability · Mathematics 2019-02-15 Octavio Arizmendi , Pilar Cano , Clemens Huemer

Two key tasks in high-dimensional regularized regression are tuning the regularization strength for accurate predictions and estimating the out-of-sample risk. It is known that the standard approach -- $k$-fold cross-validation -- is…

Statistics Theory · Mathematics 2025-10-24 Kevin Luo , Yufan Li , Pragya Sur

We compute the distance-dependent three-point function of general planar maps and of bipartite planar maps, i.e., the generating function of these maps with three marked vertices at prescribed pairwise distances. Explicit expressions are…

Combinatorics · Mathematics 2015-07-21 Éric Fusy , Emmanuel Guitter

This paper reviews generalized Pareto copulas (GPC), which turn out to be a key to multivariate extreme value theory. Any GPC can be represented in an easy analytic way using a particular type of norm on $\mathbb{R}^d$, called $D$-norm. The…

Statistics Theory · Mathematics 2018-11-26 Michael Falk , Simone Padoan , Florian Wisheckel

A graph is said to be {\em half-arc-transitive} if its automorphism group acts transitively on the set of its vertices and edges but not on the set of its arcs. With each half-arc-transitive graph of valency 4 a collection of the so called…

Combinatorics · Mathematics 2007-05-23 Primoz Sparl

Scale-invariant universal crossing probabilities are studied for critical anisotropic systems in two dimensions. For weakly anisotropic standard percolation in a rectangular-shaped system, Cardy's exact formula is generalized using a…

Statistical Mechanics · Physics 2007-05-23 L. Turban