Results 11 to 20 of about 145 (122)
A practical algorithm for weighted k‐hulls
Abstract The convex hull is a central concept in computational geometry, geometry processing, and generally for summarizing sampled data. Its descriptive power suffers significantly in the presence of noise. The k‐hull, also known as the k‐depth contour in statistics, is the intersection of all half‐spaces that contain all but k data points, i.e. it is
N. Look, H. Meyer, M. Alexa
wiley +1 more source
Abstract We give a formula with explicit constants relating the subsurface projection dY(ν−,ν+)$d_Y(\nu ^-,\nu ^+)$ of the end invariants ν−,ν+$\nu ^-,\nu ^+$ of a hyperbolic 3‐manifold Q$Q$ diffeomorphic to S×R$S\times \mathbb {R}$ and the length of the geodesic representative in Q$Q$ of the multicurve ∂Y$\partial Y$.
Gabriele Viaggi
wiley +1 more source
Lower bounds for cube‐ideal set‐systems
Abstract A set‐system S⊆{0,1}n$S\subseteq \lbrace 0,1\rbrace ^n$ is cube‐ideal if its convex hull can be described by capacity and generalized set covering inequalities. In this paper, we use combinatorics, convex geometry, and polyhedral theory to give exponential lower bounds on the size of cube‐ideal set‐systems, and linear lower bounds on their ...
Ahmad Abdi +3 more
wiley +1 more source
Identifiability of points and rigidity of hypergraphs under algebraic constraints
Abstract The identifiability problem arises naturally in a number of contexts in mathematics and computer science. Specific instances include local or global rigidity of graphs and unique completability of partially‐filled tensors subject to rank conditions.
James Cruickshank +3 more
wiley +1 more source
Circle packings, renormalizations, and subdivision rules
Abstract In this paper, we use iterations of skinning maps on Teichmüller spaces to study circle packings and develop a renormalization theory for circle packings whose nerves satisfy certain subdivision rules. We characterize when the skinning map has bounded image.
Yusheng Luo, Yongquan Zhang
wiley +1 more source
The systole of random hyperbolic 3‐manifolds
Abstract We study the systole of a model of random hyperbolic 3‐manifolds introduced in Petri and Raimbault [Comment. Math. Helv. 97 (2022), no. 4, 729–768], answering a question posed in that same article. These are compact manifolds with boundary constructed by randomly gluing truncated tetrahedra along their faces.
Anna Roig‐Sanchis
wiley +1 more source
A tropical approach to rigidity: Counting realisations of frameworks
Abstract A realisation of a graph in the plane as a bar‐joint framework is rigid if there are finitely many other realisations, up to isometries, with the same edge lengths. Each of these finitely many realisations can be seen as a solution to a system of quadratic equations prescribing the distances between pairs of points.
Oliver Clarke +6 more
wiley +1 more source
Rigidity of anti‐de Sitter (2+1)‐spacetimes with convex boundary near the Fuchsian locus
Abstract We prove that globally hyperbolic compact anti‐de Sitter (2+1)‐spacetimes with a strictly convex spacelike boundary that is either smooth or polyhedral and whose holonomy is close to Fuchsian are determined by the induced metric on the boundary.
Roman Prosanov, Jean‐Marc Schlenker
wiley +1 more source
Toric amplitudes and universal adjoints
Abstract A toric amplitude is a rational function associated with a simplicial polyhedral fan. The definition is inspired by scattering amplitudes in particle physics. We prove algebraic properties of such amplitudes and study the geometry of their zero loci. These hypersurfaces play the role of Warren's adjoint via a dual volume interpretation.
Simon Telen
wiley +1 more source
Canonical forms of oriented matroids
Abstract Positive geometries are semialgebraic sets equipped with a canonical differential form whose residues mirror the boundary structure of the geometry. Every full‐dimensional projective polytope is a positive geometry. Motivated by the canonical forms of polytopes, we construct a canonical form for any tope of an oriented matroid inside the Orlik–
Christopher Eur, Thomas Lam
wiley +1 more source

