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Several nontrivial properties are shown for the mean square radius of gyration $R_K^2$ of ring polymers with a fixed knot type K. Through computer simulation, we discuss both finite-size and asymptotic behaviors of the gyration radius under…

Soft Condensed Matter · Physics 2009-11-07 Miyuki K. Shimamura , Tetsuo Deguchi

The Lasserre's reconstruction algorithm is extended to the D-polytopes with the construction of their shape space. Thus, the areas of d-skeletons $(1\leq d\leq D)$ can be expressed as functions of the areas and normal bi-vectors of the…

General Relativity and Quantum Cosmology · Physics 2022-01-19 Gaoping Long , Yongge Ma

In view of solving problems of geometric realizability of polyhedra with given geometric constraints, we describe the space of geometric realizations of a simply-connected triangulated euclidean polyhedron in $\mathbb{R}^3$ up to similarity…

Metric Geometry · Mathematics 2017-03-10 Maria Hempel

Given a finite CW complex $K$, we use a version of the Goodwillie-Weiss tower to formulate an obstruction theory for embedding $K$ into a Euclidean space $\mathbb{R}^d$. For $2$-dimensional complexes in $\mathbb{R}^4$, a geometric analogue…

Algebraic Topology · Mathematics 2024-07-31 Gregory Arone , Vyacheslav Krushkal

This article is concerned with a geometric tool given by a pair of projector operators defined by almost product structures on finite dimensional manifolds, polarized by a distribution of constant rank and also endowed with some geometric…

Mathematical Physics · Physics 2011-10-11 Paulo Pitanga , Paulo R. Rodrigues

Classical results of Cauchy and Dehn imply that the 1-skeleton of a convex polyhedron $P$ is rigid i.e. every continuous motion of the vertices of $P$ in $\mathbb R^3$ which preserves its edge lengths results in a polyhedron which is…

Combinatorics · Mathematics 2025-03-04 James Cruickshank , Bill Jackson , Shin-ichi Tanigawa

We use the measurable Hall's theorem due to Cie\'sla and Sabok to prove that (i) if two measurable sets $A,B \subset \mathbb{R}^d$ of the same measure are bounded remainder sets with respect to a given irrational $d$-dimensional vector…

Metric Geometry · Mathematics 2026-02-13 Mark Mordechai Etkind , Sigrid Grepstad , Mihail N. Kolountzakis , Nir Lev

We introduce a cohomological obstruction to solving the constant scalar curvature K\"ahler (cscK) equation twisted by a semipositive form, appearing in works of Fine and Song-Tian. Geometrically this gives an obstruction for a manifold to…

Differential Geometry · Mathematics 2008-04-03 Jacopo Stoppa

On a M\"obius surface, as defined by D. Calderbank, we study a variant of the Einstein-Weyl (EW) equation which we call scalar-flat M\"obius EW (sf-MEW). This is a conformally invariant, finite type, overdetermined system of semi-linear…

Differential Geometry · Mathematics 2013-10-09 Matthew Randall

In this note, we obtain new obstructions to symplectic embeddings of a product of disks (a polydisk) into a 4-dimensional ball. The polydisk P(r,s) is the product of the disk of area r with the disk of area s. The ball of capacity a,…

Symplectic Geometry · Mathematics 2013-04-11 Richard Hind , Samuel Lisi

In combinatorial topology we aim to triangulate manifolds such that their topological properties are reflected in the combinatorial structure of their description. Here, we give a combinatorial criterion on when exactly triangulations of…

Geometric Topology · Mathematics 2018-10-24 Benjamin Burton , Jonathan Spreer

The Distance Geometry Problem asks for a realization of a given weighted graph in $\mathbb{R}^K$. Two variants of this problem, both originating from protein conformation, are based on a given vertex order (which abstracts the protein…

Computational Geometry · Computer Science 2021-10-05 Germano Abud , Jorge Alencar , Carlile Lavor , Leo Liberti , Antonio Mucherino

Our main result is that every n-dimensional polytope can be described by at most (2n-1) polynomial inequalities and, moreover, these polynomials can explicitly be constructed. For an n-dimensional pointed polyhedral cone we prove the bound…

Metric Geometry · Mathematics 2007-05-23 Hartwig Bosse , Martin Groetschel , Martin Henk

In this paper, we propose a topology optimization (TO) framework where the design is parameterized by a set of convex polygons. Extending feature mapping methods in TO, the representation allows for direct extraction of the geometry. In…

Optimization and Control · Mathematics 2023-05-09 Aaditya Chandrasekhar

In 1991, Yannakakis (J. Comput. System Sci., 1991) proved that no symmetric extended formulation for the matching polytope of the complete graph K_n with n nodes has a number of variables and constraints that is bounded subexponentially in…

Combinatorics · Mathematics 2015-05-14 Volker Kaibel , Kanstantsin Pashkovich , Dirk Oliver Theis

We study the scalar curvature of incomplete wedge metrics in certain stratified spaces with a single singular stratum (wedge spaces). Building upon several well established technical tools for this category of spaces (the corresponding…

Differential Geometry · Mathematics 2023-04-19 Levi Lopes de Lima

A weakly infeasible semidefinite program (SDP) has no feasible solution, but it has approximate solutions whose constraint violation is arbitrarily small. These SDPs are ill-posed and numerically often unsolvable. They are also closely…

Optimization and Control · Mathematics 2022-07-11 Gábor Pataki , Aleksandr Touzov

Provan and Billera introduced notions of (weak) decomposability of simplicial complexes as a means of attempting to prove polynomial upper bounds on the diameter of the facet-ridge graph of a simplicial polytope. Recently, De Loera and Klee…

Combinatorics · Mathematics 2023-11-14 Nicolai Hähnle , Steven Klee , Vincent Pilaud

Interesting data often concentrate on low dimensional smooth manifolds inside a high dimensional ambient space. Random projections are a simple, powerful tool for dimensionality reduction of such data. Previous works have studied bounds on…

Machine Learning · Statistics 2016-09-13 Subhaneil Lahiri , Peiran Gao , Surya Ganguli

Robertson (1988) suggested a model for the realization space of a convex d-dimensional polytope and an approach via the implicit function theorem, which -- in the case of a full rank Jacobian -- proves that the realization space is a…

Metric Geometry · Mathematics 2020-07-02 Laith Rastanawi , Rainer Sinn , Günter M. Ziegler