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The theory of quasi-arithmetic means is a powerful tool in the study of covariance functions across space-time. In the present study we use quasi-arithmetic functionals to make inferences about the permissibility of averages of functions…

Probability · Mathematics 2007-06-13 E. Porcu , J. Mateu , G. Christakos

Quasicrystals are characterized by quasi-periodic arrangements of atoms. The description of their mechanics involves deformation and a (so called phason) vector field accounting at macroscopic scale of local phase changes, due to atomic…

Mathematical Physics · Physics 2015-11-23 Luca Bisconti , Paolo Maria Mariano

The conditions for forming quasicrystals and their approximants are stringent, normally requiring multiple length scales to stabilize the quasicrystalline order. Here we report an unexpected finding that the approximants and motifs of…

Soft Condensed Matter · Physics 2026-04-30 Zhehua Jiang , Jianhua Zhang , Mengyuan Zhan , Jiaqi Si , Junchao Huang , Hua Tong , Ning Xu

Equivalence relations or, more general, quasiorders (i.e., reflexive and transitive binary relations) $\rho$ have the property that an $n$-ary operation $f$ preserves $\rho$, i.e., $f$ is a polymorphism of $\rho$, if and only if each…

Rings and Algebras · Mathematics 2023-07-06 Danica Jakubíková-Studenovská , Reinhard Pöschel , Sándor Radeleczki

In this paper, we give a realization of crystal bases for quantum affine algebras using some new combinatorial objects which we call the Young walls. The Young walls consist of colored blocks with various shapes that are built on the given…

Quantum Algebra · Mathematics 2007-05-23 Seok-Jin Kang

Introduced by C. R. Shallon in 1979, graph algebras establish a useful connection between graph theory and universal algebra. This makes it possible to investigate graph varieties and graph quasivarieties, i.e., classes of graphs described…

Rings and Algebras · Mathematics 2020-05-19 Erkko Lehtonen , Reinhard Pöschel

A (non-commutative) Ulam quasimorphism is a map $q$ from a group $\Gamma$ to a topological group $G$ such that $q(xy)q(y)^{-1}q(x)^{-1}$ belongs to a fixed compact subset of $G$. Generalizing the construction of Barge and Ghys, we build a…

Differential Geometry · Mathematics 2025-01-13 Michael Brandenbursky , Misha Verbitsky

We show that the Hopf algebra of quasi-symmetric functions arises naturally as the integral Chow ring of the algebraic stack of expanded pairs originally described by J. Li, using a more combinatorial description in terms of configurations…

Algebraic Geometry · Mathematics 2018-06-29 Jakob Oesinghaus

We generalize the results for Banach algebras of pseudodifferential operators obtained by Gr\"ochenig and Rzeszotnik in [24] to quasi-algebras of Fourier integral operators. Namely, we introduce quasi-Banach algebras of symbol classes for…

Functional Analysis · Mathematics 2023-02-13 Elena Cordero , Gianluca Giacchi

We introduce the new notion of the "quasi-Galois point" in Algebraic geometry, which is a generalization of the Galois point. A point $P$ in projective plane is said to be quasi-Galois for a plane curve if the curve admits a non-trivial…

Algebraic Geometry · Mathematics 2016-03-04 Satoru Fukasawa , Kei Miura , Takeshi Takahashi

The notion of quasi-unit has been introduced by Yosida in unital Riesz spaces. Later on, a fruitful potential theoretic generalization was obtained by Arsove and Leutwiler. Due to the work of Eriksson and Leutwiler, this notion also turned…

Functional Analysis · Mathematics 2018-01-03 Zsigmond Tarcsay , Tamás Titkos

Graphs and various graph-like combinatorial structures, such as preorders and hypergraphs, are ubiquitous in programming. This paper focuses on representing graphs in a purely functional programming language like Haskell. There are several…

Programming Languages · Computer Science 2022-02-21 Andrey Mokhov

Quasicrystals are long-range ordered, yet not periodic, and thereby present a fascinating challenge for condensed matter physics, as one cannot resort to the usual toolbox based on Bloch's theorem. Here, we present a numerical method for…

Disordered Systems and Neural Networks · Physics 2023-04-18 Emmanuel Gottlob , Ulrich Schneider

The quasi-Clifford algebras, and their Wedderburn structure and representation theory, as described by Gastineau-Hills in 1980 and 1982, should be better known, and have only recently been rediscovered. These algebras and their…

Combinatorics · Mathematics 2019-04-22 Paul C. Leopardi

Modulated crystals and quasicrystals can simultaneously be described as modulated quasicrystals, a class of point sets introduced by de Bruijn in 1987. With appropriate modulation functions, modulated quasicrystals themselves constitute a…

Dynamical Systems · Mathematics 2024-09-05 Jeong-Yup Lee , Daniel Lenz , Christoph Richard , Bernd Sing , Nicolae Strungaru

We exhibit new examples of double quasi-Poisson brackets, based on some classification results and the method of fusion. This method was introduced by Van den Bergh for a large class of double quasi-Poisson brackets which are said…

Quantum Algebra · Mathematics 2022-08-24 Maxime Fairon

Linearly repetitive cut and project sets are mathematical models for perfectly ordered quasicrystals. In a previous paper we presented a characterization of linearly repetitive cut and project sets. In this paper we extend the classical…

Dynamical Systems · Mathematics 2015-09-29 Alan Haynes , Henna Koivusalo , James Walton

Invariant classes under parabolic and near-parabolic renormalization have proved extremely useful for studying the dynamics of polynomials. The first such class was introduced by Inou-Shishikura to study quadratic polynomials; their…

Dynamical Systems · Mathematics 2026-02-24 Alex Kapiamba

We study quasi-morphisms on the groups Pn of pure braids on n strings and on the group D of compactly supported area-preserving diffeomorphisms of an open two-dimensional disc. We show that it is possible to build quasi-morphisms on Pn by…

Geometric Topology · Mathematics 2012-07-03 Michael Brandenbursky

Let g be a complex, semisimple Lie algebra. We prove the existence of a quasi-Coxeter, quasitriangular quasibialgebra structure on the enveloping algebra of g, which binds the quasi-Coxeter structure underlying the Casimir connection of g…

Quantum Algebra · Mathematics 2016-01-19 Valerio Toledano-Laredo