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We show that the order dimension of the weak order on a Coxeter group of type A, B or D is equal to the rank of the Coxeter group, and give bounds on the order dimensions for the other finite types. This result arises from a unified…

Combinatorics · Mathematics 2026-05-13 Nathan Reading

The characteristic feature of the adeles is that they involve localizations of products (or equivalently restricted products of localizations). The point of this paper is to introduce an adelic style cohomological invariant of a partially…

Commutative Algebra · Mathematics 2019-03-08 J. P. C. Greenlees

We generalise the insertion into a binary heap to any directed acyclic graph (DAG) with one source vertex. This lets us formulate a general method for converting any such DAG into a data structure with priority queue interface. We apply our…

Data Structures and Algorithms · Computer Science 2017-10-04 Mikhail Gudim

In 2015, Felsner, Trotter, and Wiechert showed that posets with outerplanar cover graphs have bounded dimension. We generalise this result to posets with $k$-outerplanar cover graphs. Namely, we show that posets with $k$-outerplanar cover…

Combinatorics · Mathematics 2021-05-04 Maximilian Gorsky , Michał T. Seweryn

Boij and S\"oderberg made a pair of conjectures, which were subsequently proven by Eisenbud and Schreyer and then extended by Boij and S\"oderberg, about the structure of Betti diagrams of Graded modules. In the theory, a particular family…

Combinatorics · Mathematics 2011-02-25 David Cook

For any graded poset $P$, we define a new graded poset, $\mathcal E(P)$, whose elements are the edges in the Hasse diagram of P. For any group, $G$, acting on the boolean algebra, $B_n$, we conjecture that $\mathcal E(B_n/G)$ is Peck. We…

Combinatorics · Mathematics 2017-12-12 David Hemminger , Aaron Landesman , Zijian Yao

This paper presents combinatorial facts dealing with the number of unlabeled partially ordered sets (posets) refined by the number of arcs in the Hasse diagram (sequence A342447 in OEIS). The main result is that the differences with respect…

Combinatorics · Mathematics 2025-12-10 Rico Zöllner , Konrad Handrich

Divisible design digraphs are constructed from skew balanced generalized weighing matrices and generalized Hadamard matrices. Commutative and non-commutative association schemes are shown to be attached to the constructed divisible design…

Combinatorics · Mathematics 2020-09-07 Hadi Kharaghani , Sho Suda

A Vogan diagram is a Dynkin diagram of a Kac-Moody Lie algebra of finite or affine type overlayed with additional structures. This paper develops the theory of Vogan diagrams for almost compact real forms of indecomposable twisted affine…

Rings and Algebras · Mathematics 2008-08-01 Tanusree Pal

The coefficients of the chain polynomial of a finite poset enumerate chains in the poset by their number of elements. It has been a challenging open problem to determine which posets have real-rooted chain polynomials. Two new classes of…

Combinatorics · Mathematics 2025-12-02 Christos A. Athanasiadis , Theo Douvropoulos , Katerina Kalampogia-Evangelinou

In order to be able to use methods of Universal Algebra for investigating posets, we assign to every pseudocomplemented poset, to every relatively pseudocomplemented poset and to every sectionally pseudocomplemented poset a certain algebra…

Rings and Algebras · Mathematics 2021-03-24 Ivan Chajda , Helmut Länger

We study homology groups of posets with functor coefficients and apply our results to give a novel approach to study Khovanov homology of knots and related homology theories.

Algebraic Topology · Mathematics 2019-07-10 Nicolás Cianci , Miguel Ottina

Joret et al. proved that posets with cover graphs of treewidth at most 2 have dimension at most 1276. Their proof is long and very complex. We give a short and much simpler proof that the dimension of such posets is at most 12.

Combinatorics · Mathematics 2019-06-18 Michał T. Seweryn

Inspired by Zhao and Xu's study on which a dcpo can be determined by its Scott closed subsets lattice, we further investigate whether a poset (or dcpo) $P$ is able to be determined by the family $\mathcal Q(P)$ of its Scott compact…

General Topology · Mathematics 2025-03-05 Huijun Hou , Qingguo Li

We define 2-gerbes bound by complexes of braided group-like stacks. We prove a classification result in terms of hypercohomology groups with values in abelian crossed squares and cones of morphisms of complexes of length 3. We give an…

Category Theory · Mathematics 2008-08-28 Ettore Aldrovandi

Divisible design digraphs which can be obtained as Cayley digraphs are studied. A characterization of divisible design Cayley digraphs in terms of the generating sets is given. Further, we give several constructions of divisible design…

Combinatorics · Mathematics 2019-10-25 Dean Crnkovic , Hadi Kharaghani , Andrea Svob

Partially ordered sets labeled with k labels (k-posets) and their homomorphisms are examined. We give a representation of directed graphs by k-posets; this provides a new proof of the universality of the homomorphism order of k-posets. This…

Combinatorics · Mathematics 2016-11-22 Leonard Kwuida , Erkko Lehtonen

In this paper we review the coset construction for winding subalgebras of affine Lie algebras. We classify all cosets of central charge $\hat c<1$ and calculate their branching rules. The corresponding character identities give certain…

q-alg · Mathematics 2008-02-03 Peter Bouwknegt

We define several sorts of mappings on a poset like monotone, strictly monotone, upper cone preserving and variants of these. Our aim is to characterize posets in which some of these mappings coincide. We define special mappings determined…

Combinatorics · Mathematics 2021-03-01 Ivan Chajda , Helmut Länger

We construct elements of the third quandle homology groups of knot quandles, which are called the shadow fundamental classes. They play the same roles for the shadow quandle cocycle invariants of knots as the fundamental classes of knot…

Geometric Topology · Mathematics 2009-06-04 Yasto Kimura