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In this work, we provide a way of constructing new semiorthogonal decompositions using metric techniques (\`a la Neeman). Given a semiorthogonal decomposition on a category with a special kind of metric, which we call a compressible metric,…

Algebraic Geometry · Mathematics 2025-04-17 Kabeer Manali Rahul

The Random Projection Tree structures proposed in [Freund-Dasgupta STOC08] are space partitioning data structures that automatically adapt to various notions of intrinsic dimensionality of data. We prove new results for both the RPTreeMax…

Data Structures and Algorithms · Computer Science 2012-11-01 Aman Dhesi , Purushottam Kar

We introduce a concept of tree-graded metric space and we use it to show quasi-isometry invariance of certain classes of relatively hyperbolic groups, to obtain a characterization of relatively hyperbolic groups in terms of their asymptotic…

Geometric Topology · Mathematics 2009-09-29 Cornelia Drutu , Mark Sapir

We define a notion of a rotund quasi-uniform space and describe a new direct construction of a (right-continuous) quasi-pseudometric on a (rotund) quasi-uniform space. This new construction allows to give alternative proofs of several…

General Topology · Mathematics 2016-02-19 Taras Banakh , Alex Ravsky

Metric embeddings are central to metric theory and its applications. Here we consider embeddings of a different sort: maps from a set to subsets of a metric space so that distances between points are approximated by minimal distances…

Metric Geometry · Mathematics 2025-08-13 David Bryant , Katharina T. Huber , Vincent Moulton , Andreas Spillner

We show that the standard definitions of Sasaki structures have elegant and simplifying interpretations in terms of projective differential geometry. For Sasaki-Einstein structures we use projective geometry to provide a resolution of such…

Differential Geometry · Mathematics 2019-12-09 A. Rod Gover , Katharina Neusser , Travis Willse

We present a streamlined exposition of a construction by R. Chen, A. Poulin, R. Tao, and A. Tserunyan, which proves the treeability of equivalence relations generated by any locally-finite Borel graph such that each component is a…

Logic · Mathematics 2025-04-25 Zhaoshen Zhai

It is proved that the sum of the Loewy lengths of the homology modules of a finite free complex F over a local ring R is bounded below by a number depending only on R. This result uncovers, in the structure of modules of finite projective…

Commutative Algebra · Mathematics 2010-05-20 L. L. Avramov , R. -O. Buchweitz , S. B. Iyengar , C. Miller

We develop a theory of quasi-Lie bialgebroids using a homological approach. This notion is a generalization of quasi-Lie bialgebras, as well as twisted Poisson structures with a 3-form background which have recently appeared in the context…

Quantum Algebra · Mathematics 2007-05-23 Dmitry Roytenberg

We devise a generalization of tree approximation that generates conforming meshes, i.e., meshes with a particular structure like edge-to-edge triangulations. A key feature of this generalization is that the choices of the cells to be…

Numerical Analysis · Mathematics 2023-01-26 Peter Binev , Francesca Fierro , Andreas Veeser

This paper continues a geometric study of Harvey's Complex of Curves, whose ultimate goal is to apply the theory of hyperbolic spaces and groups to algorithmic questions for the Mapping Class Group and geometric properties of Kleinian…

Geometric Topology · Mathematics 2007-05-23 Howard A. Masur , Yair N. Minsky

Simple constructions are given for finite semifields that include as special cases both old semifields and recently constructed semifields.

Combinatorics · Mathematics 2012-01-04 Juergen Bierbrauer , William M. Kantor

In this paper, we study metric trees, without any finiteness restrictions. For subsets of such trees, a condition that guarantees that the Hausdorff and Gromov--Hausdorff distances from the subset to the entire metric tree are the same is…

Metric Geometry · Mathematics 2024-12-30 A. O. Ivanov , I. N. Mikhailov , A. A. Tuzhilin

We give an alternative proof of the Bestvina--Feighn combination theorem for trees hyperbolic spaces and describe uniform quasigeodesics in such spaces. As one of the applications, we prove the existence of Cannon-Thurston maps for…

Group Theory · Mathematics 2022-02-22 Michael Kapovich , Pranab Sardar

Projective structures on compact real manifolds are classical objects in real differential geometry. Complex manifolds with a holomorphic projective structure on the other hand form a special class as soon as the dimension is greater than…

Algebraic Geometry · Mathematics 2015-03-02 Priska Jahnke , Ivo Radloff

In an earlier paper we showed that we can improve results by Emmy Noether and Alexander Ostrowski concerning the reducibility modulo p of absolutely irreducible polynomials with integer coefficients by giving the problem a geometric turn…

Number Theory · Mathematics 2007-05-23 Reinie Erne

Quasi-isometries are mappings on graphs, with distance-distortions parameterized by a multiplicative factor and an additive constant. The distance-distortions of quasi-isometries are in a general form that captures a wide range of…

Data Structures and Algorithms · Computer Science 2022-08-22 Khí-Uí Soo , Bakhadyr Khoussainov , Simone Linz

The main purpose of this paper is to provide a structure theorem for codimension one singular transversely projective foliationson projective manifolds. To reach our goal, we firstly extend Corlette-Simpson's classification of rank two…

Algebraic Geometry · Mathematics 2016-07-05 Frank Loray , Frédéric Touzet , Jorge Vitorio Pereira

Gorenstein projection plays a key role in birational geometry; the typical example is the linear projection of a del Pezzo surface of degree d to one of degree d-1, but variations on the same idea provide many of the classical and modern…

Algebraic Geometry · Mathematics 2007-05-23 Stavros Papadakis , Miles Reid

An important result in real algebraic geometry is the projection theorem: every projection of a semialgebraic set is again semialgebraic. This theorem and some of its conclusions lie at the basis of many other results, for example the…

Functional Analysis · Mathematics 2017-09-26 Tom Drescher , Tim Netzer , Andreas Thom