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An asteroidal triple free graph is a graph such that for every independent triple of vertices no path between any two avoids the third. In a recent result from Corneil and Stacho, these graphs were characterised through a linear vertex…

Discrete Mathematics · Computer Science 2018-07-16 Jesse Beisegel

It is known that the flip distance between two triangulations of a convex polygon is related to the minimum number of tetrahedra in the triangulation of some polyhedron. It is interesting to know whether these two numbers are the same. In…

Geometric Topology · Mathematics 2022-05-25 Zili Wang

We study the configuration space of rectangulations and convex subdivisions of $n$ points in the plane. It is shown that a sequence of $O(n\log n)$ elementary flip and rotate operations can transform any rectangulation to any other…

Discrete Mathematics · Computer Science 2023-06-22 Eyal Ackerman , Michelle M. Allen , Gill Barequet , Maarten Löffler , Joshua Mermelstein , Diane L. Souvaine , Csaba D. Tóth

Topological band theory has revolutionized our understanding of electronic structure of materials, in particular, a novel state - Weyl semimetal - has been predicted for systems with strong spin-orbit coupling (SOC). Here, a new class of…

Materials Science · Physics 2015-10-20 Yuanping Chen , Yuee Xie , Shengyuan A. Yang , Hui Pan , Fan Zhang , Marvin L. Cohen , Shengbai Zhang

A branched affine structure on a compact topological surface with marked points is a complex affine structure outside the marked points. We give a proof of an unpublished foundational theorem of Veech, stating that any branched affine…

Geometric Topology · Mathematics 2019-12-04 Guillaume Tahar

Consider a graph $G$ drawn on a fixed surface, and assign to each vertex a list of colors of size at least two if $G$ is triangle-free and at least three otherwise. We prove that we can give each vertex a color from its list so that each…

Combinatorics · Mathematics 2021-11-16 Zdeněk Dvořák , Sergey Norin

Through triglobal resolvent analysis, we reveal the effects of wing tip and sweep angle on laminar separated wakes over swept wings. For the present study, we consider wings with semi-aspect ratios from $1$ to $4$, sweep angles from…

Fluid Dynamics · Physics 2022-12-06 Jean Hélder Marques Ribeiro , Chi-An Yeh , Kunihiko Taira

In this paper, I presented the analysis and numerical results for free transverse vibration of thin rectangular plates having arbitrarily varying non-homogeneity with the in-plane coordinates along the two concurrent edges. For finding the…

Classical Physics · Physics 2018-10-16 Avinash Kumar

Due to their topological charge, or chirality, the Weyl cones present in topological semimetals are considered robust against arbitrary perturbations. One well-understood exception to this robustness is the pairwise creation or annihilation…

Mesoscale and Nanoscale Physics · Physics 2021-11-19 Viktor Könye , Adrien Bouhon , Ion Cosma Fulga , Robert-Jan Slager , Jeroen van den Brink , Jorge I. Facio

We study flip-graphs of triangulations on topological surfaces where distance is measured by counting the number of necessary flip operations between two triangulations. We focus on surfaces of positive genus $g$ with a single boundary…

Geometric Topology · Mathematics 2017-09-04 Hugo Parlier , Lionel Pournin

Trigonometric invariants are defined for each Weyl group orbit on the root lattice. They are real and periodic on the coroot lattice. Their polynomial algebra is spanned by a basis which is calculated by means of an algorithm. The…

Mathematical Physics · Physics 2009-10-31 Oliver Haschke , Werner Ruehl

For the root system of type $B_l$ and $C_l$, we generalize the result of \cite{DZ1998} by showing the existence of a Frobenius manifold structure on the orbit space of the extended affine Weyl group that corresponds to any vertex of the…

Differential Geometry · Mathematics 2007-05-23 Boris Dubrovin , Youjin Zhang , Dafeng Zuo

We generalize I. Frenkel's orbital theory for non twisted affine Lie algebras to the case of twisted affine Lie algebras using a character formula for certain non-connected compact Lie groups.

Representation Theory · Mathematics 2007-05-23 Robert Wendt

We theoretically study the effects of electron-electron interaction in twisted bilayer graphene in applied transverse dc electric field. When the twist angle is not very small, the electronic spectrum of the bilayer consists of four Dirac…

Strongly Correlated Electrons · Physics 2018-07-04 A. O. Sboychakov , A. V. Rozhkov , A. L. Rakhmanov , Franco Nori

The paper concerns lattice triangulations, that is, triangulations of the integer points in a polygon in $\mathbb{R}^2$ whose vertices are also integer points. Lattice triangulations have been studied extensively both as geometric objects…

Probability · Mathematics 2015-06-03 Pietro Caputo , Fabio Martinelli , Alistair Sinclair , Alexandre Stauffer

In this paper, we give a polynomial time algorithm which determines if a given triangle-free graph with no induced seven-vertex path is 3-colorable, and gives an explicit coloring if one exists.

Combinatorics · Mathematics 2014-09-19 Maria Chudnovsky , Peter Maceli , Mingxian Zhong

We address the following question: When an affine cone over a smooth Fano threefold admits an effective action of the additive group? In this paper we deal with Fano threefolds of index 1 and Picard number 1. Our approach is based on a…

Algebraic Geometry · Mathematics 2011-06-08 Takashi Kishimoto , Yuri Prokhorov , Mikhail Zaidenberg

We give an exact characterization of 3-colorability of triangle-free graphs drawn in the torus, in the form of 186 "templates" (graphs with certain faces filled by arbitrary quadrangulations) such that a graph from this class is not…

Combinatorics · Mathematics 2020-09-03 Zdeněk Dvořák , Jakub Pekárek

For a finite triangulation of the plane with faces properly coloured white and black, let A be the abelian group constructed by labelling the vertices with commuting indeterminates and adding relations which say that the labels around each…

Combinatorics · Mathematics 2015-05-04 Nicholas J. Cavenagh , Ian M. Wanless

The triangulations of a surface $\Sigma$ with a prescribed set of vertices can be endowed with a graph structure $\mathcal{F}(\Sigma)$. Its edges connect two triangulations that differ by a single arc. It is known that, when $\Sigma$ is a…

Geometric Topology · Mathematics 2021-09-14 Lionel Pournin , Zili Wang