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We provide a deterministic polynomial-time algorithm that, for a given $k$-uniform hypergraph $H$ with $n$ vertices and edge density $d$, finds a complete $k$-partite subgraph of $H$ with parts of size at least ${c(d, k)(\log…

Combinatorics · Mathematics 2026-02-23 Ferran Espuña

Let $k$ be a positive integer and let $G$ be a graph with $n$ vertices. A connected $k$-subpartition of $G$ is a collection of $k$ pairwise disjoint sets (a.k.a. classes) of vertices in $G$ such that each set induces a connected subgraph.…

Combinatorics · Mathematics 2025-12-23 Phablo F. S. Moura , Hande Yaman , Roel Leus

Let $\mathrm{G}$ be a subgroup of the symmetric group $\mathfrak S(U)$ of all permutations of a countable set $U$. Let $\overline{\mathrm{G}}$ be the topological closure of $\mathrm{G}$ in the function topology on $U^U$. We initiate the…

Combinatorics · Mathematics 2020-02-13 Claude Laflamme , Maurice Pouzet , Norbert Sauer , Robert Woodrow

The computation of the index of the Hessian of the action functional in semi-Riemannian geometry at geodesics with two variable endpoints is reduced to the case of a fixed final endpoint. Using this observation, we give an elementary proof…

Differential Geometry · Mathematics 2009-10-31 Paolo Piccione , Daniel Victor Tausk

Until this work, the packing radius of a poset code was only known in the cases where the poset was a chain, a hierarchy, a union of disjoint chains of the same size, and for some families of codes. Our objective is to approach the general…

Information Theory · Computer Science 2013-01-28 Rafael Gregorio Lucas D'Oliveira , Marcelo Firer

In this article, we give two extended space formulations, respectively, for the induced tree and path polytopes of chordal graphs with vertex and edge variables. These formulations are obtained by proving that the induced tree and path…

Discrete Mathematics · Computer Science 2026-01-14 Alexandre Dupont-Bouillard

Starting from the data of an arbor, which is a rooted tree with vertices decorated by disjoint sets, we introduce a lattice polytope and a partial order on its lattice points. We give recursive algorithms for various classical invariants of…

Combinatorics · Mathematics 2025-08-26 Frédéric Chapoton

This is the last in a series of papers where we prove a conjecture of Deser and Schwimmer regarding the algebraic structure of ``global conformal invariants''; these are defined to be conformally invariant integrals of geometric scalars.…

Differential Geometry · Mathematics 2009-12-21 Spyros Alexakis

A partially ordered set is r-thick if every nonempty open interval contains at least r elements. This paper studies the flag vectors of graded, r-thick posets and shows the smallest convex cone containing them is isomorphic to the cone of…

Combinatorics · Mathematics 2007-05-23 Margaret M. Bayer , Gabor Hetyei

A result of Foxby states that if there exists a complex with finite depth, finite flat dimension, and finite injective dimension over a local ring $R$, then $R$ is Gorenstein. In this paper we investigate some homological dimensions…

Commutative Algebra · Mathematics 2015-04-10 Sean Sather-Wagstaff , Jonathan Totushek

For a large class of semiclassical pseudodifferential operators, including Schr\"odinger operators, $ P (h) = -h^2 \Delta_g + V (x) $, on compact Riemannian manifolds, we give logarithmic lower bounds on the mass of eigenfunctions outside…

Spectral Theory · Mathematics 2009-08-18 Hans Christianson

The notion of denominator vectors can be extended to all generic basis elements of upper cluster algebras in a natural way. Under a weakened version of generic pairing assumption, we provide a representation-theoretic interpretation for…

Representation Theory · Mathematics 2025-06-05 Jiarui Fei

Let $k,r \geq 2$ be two integers. We consider the problem of partitioning the hyperedge set of an $r$-uniform hypergraph $H$ into the minimum number $\chi_k'(H)$ of edge-disjoint subhypergraphs in which every vertex has either degree $0$ or…

Combinatorics · Mathematics 2025-10-07 Gaia Carenini , Samuel Coulomb

Using a K-theory point of view, Bott related the Atiyah-Singer index theorem for elliptic operators on compact homogeneous spaces to the Weyl character formula. This article explains how to prove the local index theorem for compact…

Functional Analysis · Mathematics 2016-04-12 Seunghun Hong

Relations between Gorenstein derived categories, Gorenstein defect categories and Gorenstein stable categories are established. Using these, the Gorensteinness of an algebra $A$ and invariants with respect to recollements of the bounded…

Representation Theory · Mathematics 2014-02-14 Nan Gao

In a paper by Holm and Jorgensen, the cluster category $\mathscr{D}$ of type $A_\infty$, with Auslander-Reiten quiver $\mathbb{Z} A_\infty$, is introduced. Slices in the Auslander-Reiten quiver of $\mathscr{D}$ give rise to direct systems;…

Representation Theory · Mathematics 2016-02-26 Thomas A. Fisher

We classify all the possible $delta$-vectors of d-dimensional integral convex polytopes whose volumes are less than or equal to 3/(d!).

Combinatorics · Mathematics 2009-04-24 Takayuki Hibi , Akihiro Higashitani , Yuuki Nagazawa

We introduce a notion of intrinsically H\"older graphs in metric spaces. Following a recent paper of Le Donne and the author, we prove some relevant results as the Ascoli-Arzel\`a compactness Theorem, Ahlfors-David regularity and the…

Metric Geometry · Mathematics 2022-07-21 Daniela Di Donato

Designing coresets--small-space sketches of the data preserving cost of the solutions within $(1\pm \epsilon)$-approximate factor--is an important research direction in the study of center-based $k$-clustering problems, such as $k$-means or…

Computational Geometry · Computer Science 2023-03-03 Sayan Bandyapadhyay , Fedor V. Fomin , Tanmay Inamdar

We provide an expository introduction to Euclidean Scissors Congruence, the study of polytopes in Euclidean space up to `cut and paste' relations. We first re-frame questions in scissors congruence as those in group homology. We then use…

Algebraic Topology · Mathematics 2025-02-06 Anubhav Nanavaty