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Related papers: $q$-Analogs of strongly regular graphs

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In 2022, the second author found a prolific construction of strongly regular graphs, which is based on joining a coclique and a divisible design graph with certain parameters. The construction produces strongly regular graphs with the same…

Combinatorics · Mathematics 2023-06-16 Alexander L. Gavrilyuk , Vladislav V. Kabanov

We present quantum graphs with remarkably regular spectral characteristics. We call them {\it regular quantum graphs}. Although regular quantum graphs are strongly chaotic in the classical limit, their quantum spectra are explicitly…

Quantum Physics · Physics 2009-11-07 Yu. Dabaghian , R. V. Jensen , R. Blümel

We determine new upper bounds for the clique numbers of strongly regular graphs in terms of their parameters. These bounds improve on the Delsarte bound for infinitely many feasible parameter tuples for strongly regular graphs, including…

Combinatorics · Mathematics 2019-01-31 Gary R. W. Greaves , Leonard H. Soicher

In this paper, we give constructions of strongly regular Cayley graphs and skew Hadamard difference sets. Both constructions are based on choosing cyclotomic classes in finite fields, and our results generalize ten of the eleven sporadic…

Combinatorics · Mathematics 2012-03-01 Koji Momihara

We use the theory of q-characters to establish a number of short exact sequences in the category of finite-dimensional representations of the quantum affine groups of types A and B. That allows us to introduce a set of 3-term recurrence…

Quantum Algebra · Mathematics 2012-12-07 E. Mukhin , C. A. S. Young

We give a combinatorial characterization of the group of quasiconformal homeomorphisms of a closed, oriented surface $S$ of genus at least $2$. In particular, we prove they are exactly the automorphisms of a graph of essential quasicircles…

Geometric Topology · Mathematics 2026-01-16 Katherine Williams Booth , Alexander Nolte , Yvon Verberne

We study some properties of graphs (or, rather, graph sequences) defined by demanding that the number of subgraphs of a given type, with vertices in subsets of given sizes, approximatively equals the number expected in a random graph. It…

Combinatorics · Mathematics 2014-05-28 Svante Janson , Vera T. Sós

A graph G is {\xi}-nearly planar if it can be embedded in the sphere so that each of its edges is crossed at most {\xi} times. The family of {\xi}-nearly planar graphs is widely extending the notion of planarity. We introduce an alternative…

Combinatorics · Mathematics 2013-11-04 Alexander Grigoriev , Athanassios Koutsonas , Dimitrios M. Thilikos

In 1988, Duval introduced the concept of directed strongly regular graphs, which can be viewed as a directed graph version of strongly regular graphs. Such directed graphs have similar structural and algebraic properties to strongly regular…

Combinatorics · Mathematics 2022-11-02 Xueyi Huang , Lu Lu , Jongyook Park

In 2002, D. Fon-Der-Flaass constructed a prolific family of strongly regular graphs. In this paper, we prove that for infinitely many natural numbers $n$, this family contains $n^{\Omega(n^{2/3})}$ strongly regular $n$-vertex graphs $X$…

Combinatorics · Mathematics 2023-12-04 Jinzhuan Cai , Jin Guo , Alexander L. Gavrilyuk , Ilia Ponomarenko

We give an expression of the $q$-analogues of the multiplicities of weights in irreducible $\sl_{n+1}$-modules in terms of the geometry of the crystal graph attached to the corresponding $U_q(\sl_{n+1})$-modules. As an application, we…

q-alg · Mathematics 2009-10-28 A. Lascoux , B. Leclerc , J. -Y. Thibon

We describe the relationships between the notion of $q$-deformed rational numbers, introduced in our previous work with Sophie Morier-Genoud, and the theory of dimer models. We show that $q$-deformed rationals can be calculated in terms of…

Combinatorics · Mathematics 2025-10-21 Valentin Ovsienko

We give a general construction leading to different non-isomorphic families $\Gamma_{n,q}(\K)$ of connected $q$-regular semisymmetric graphs of order $2q^{n+1}$ embedded in $\PG(n+1,q)$, for a prime power $q=p^h$, using the linear…

Combinatorics · Mathematics 2013-01-10 Philippe Cara , Sara Rottey , Geertrui Van de Voorde

A tutorial introduction is given to q-special functions and to q-analogues of the classical orthogonal polynomials, up to the level of Askey-Wilson polynomials.

Classical Analysis and ODEs · Mathematics 2013-10-15 Tom H. Koornwinder

We address the problem of defining graph transformations by the simultaneous application of direct transformations even when these cannot be applied independently of each other. An algebraic approach is adopted, with production rules of the…

Logic in Computer Science · Computer Science 2019-04-19 Thierry Boy de la Tour , Rachid Echahed

In this paper, we provide a general framework for counting geometric structures in pseudo-random graphs. As applications, our theorems recover and improve several results on the finite field analog of questions originally raised in the…

Combinatorics · Mathematics 2025-04-30 Thang Pham , Steven Senger , Michael Tait , Vu Thi Huong Thu

Working in homotopy type theory, we provide a systematic study of homotopy limits of diagrams over graphs, formalized in the Coq proof assistant. We discuss some of the challenges posed by this approach to formalizing homotopy-theoretic…

Logic · Mathematics 2019-02-20 Jeremy Avigad , Chris Kapulkin , Peter LeFanu Lumsdaine

In 2011, Penttila and Williford constructed an infinite new family of primitive $Q$-polynomial 3-class association schemes, not arising from distance regular graphs, by exploring the geometry of the lines of the unitary polar space…

Combinatorics · Mathematics 2020-09-08 Giusy Monzillo , Alessandro Siciliano

We identify a set of quantum graphs with unique and precisely defined spectral properties called {\it regular quantum graphs}. Although chaotic in their classical limit with positive topological entropy, regular quantum graphs are…

Quantum Physics · Physics 2009-11-07 R. Blümel , Yu. Dabaghian , R. V. Jensen

In this paper we construct the q-analogue of Barnes' Bernoulli numbers and plynomials of degree 2, which is an answer to a part of Schlosser's question. Finally, we treat the q-analogue of the sums of powers of consecutive integrs.

Number Theory · Mathematics 2007-05-23 Y. Simsek , D. Kim , T. Kim , S. -H. Rim