A Random Tiling Model for Two Dimensional Electrostatics

A Random Tiling Model for Two Dimensional Electrostatics
Author: Mihai Ciucu
Publisher: American Mathematical Soc.
Total Pages: 162
Release: 2005
Genre: Mathematics
ISBN: 082183794X

Studies the correlation of holes in random lozenge (i.e., unit rhombus) tilings of the triangular lattice. This book analyzes the joint correlation of these triangular holes when their complement is tiled uniformly at random by lozenges.

The Scaling Limit of the Correlation of Holes on the Triangular Lattice with Periodic Boundary Conditions

The Scaling Limit of the Correlation of Holes on the Triangular Lattice with Periodic Boundary Conditions
Author: Mihai Ciucu
Publisher: American Mathematical Soc.
Total Pages: 118
Release: 2009-04-10
Genre: Science
ISBN: 0821843265

The author defines the correlation of holes on the triangular lattice under periodic boundary conditions and studies its asymptotics as the distances between the holes grow to infinity. He proves that the joint correlation of an arbitrary collection of triangular holes of even side-lengths (in lattice spacing units) satisfies, for large separations between the holes, a Coulomb law and a superposition principle that perfectly parallel the laws of two dimensional electrostatics, with physical charges corresponding to holes, and their magnitude to the difference between the number of right-pointing and left-pointing unit triangles in each hole. The author details this parallel by indicating that, as a consequence of the results, the relative probabilities of finding a fixed collection of holes at given mutual distances (when sampling uniformly at random over all unit rhombus tilings of the complement of the holes) approach, for large separations between the holes, the relative probabilities of finding the corresponding two dimensional physical system of charges at given mutual distances. Physical temperature corresponds to a parameter refining the background triangular lattice. He also gives an equivalent phrasing of the results in terms of covering surfaces of given holonomy. From this perspective, two dimensional electrostatic potential energy arises by averaging over all possible discrete geometries of the covering surfaces.

Handbook of Enumerative Combinatorics

Handbook of Enumerative Combinatorics
Author: Miklos Bona
Publisher: CRC Press
Total Pages: 1073
Release: 2015-03-24
Genre: Mathematics
ISBN: 1482220865

Presenting the state of the art, the Handbook of Enumerative Combinatorics brings together the work of today's most prominent researchers. The contributors survey the methods of combinatorial enumeration along with the most frequent applications of these methods.This important new work is edited by Miklos Bona of the University of Florida where he

Equivalences of Classifying Spaces Completed at the Prime Two

Equivalences of Classifying Spaces Completed at the Prime Two
Author: Robert Oliver
Publisher: American Mathematical Soc.
Total Pages: 116
Release: 2006
Genre: Mathematics
ISBN: 0821838288

We prove here the Martino-Priddy conjecture at the prime $2$: the $2$-completions of the classifying spaces of two finite groups $G$ and $G'$ are homotopy equivalent if and only if there is an isomorphism between their Sylow $2$-subgroups which preserves fusion. This is a consequence of a technical algebraic result, which says that for a finite group $G$, the second higher derived functor of the inverse limit vanishes for a certain functor $\mathcal{Z}_G$ on the $2$-subgroup orbit category of $G$. The proof of this result uses the classification theorem for finite simple groups.

The Art of Mathematics

The Art of Mathematics
Author: Béla Bollobás
Publisher: Cambridge University Press
Total Pages: 392
Release: 2006-09-14
Genre: Mathematics
ISBN: 1139936662

Can a Christian escape from a lion? How quickly can a rumour spread? Can you fool an airline into accepting oversize baggage? Recreational mathematics is full of frivolous questions where the mathematician's art can be brought to bear. But play often has a purpose. In mathematics, it can sharpen skills, provide amusement, or simply surprise, and books of problems have been the stock-in-trade of mathematicians for centuries. This collection is designed to be sipped from, rather than consumed in one sitting. The questions range in difficulty: the most challenging offer a glimpse of deep results that engage mathematicians today; even the easiest prompt readers to think about mathematics. All come with solutions, many with hints, and most with illustrations. Whether you are an expert, or a beginner or an amateur mathematician, this book will delight for a lifetime.

A Sharp Threshold for Random Graphs with a Monochromatic Triangle in Every Edge Coloring

A Sharp Threshold for Random Graphs with a Monochromatic Triangle in Every Edge Coloring
Author: Ehud Friedgut
Publisher: American Mathematical Soc.
Total Pages: 80
Release: 2006
Genre: Mathematics
ISBN: 0821838253

Let $\cal{R}$ be the set of all finite graphs $G$ with the Ramsey property that every coloring of the edges of $G$ by two colors yields a monochromatic triangle. In this paper the authors establish a sharp threshold for random graphs with this property. Let $G(n, p)$ be the random graph on $n$ vertices with edge probability $p$. The authors prove that there exists a function $\widehat c=\widehat c(n)=\Theta(1)$ such that for any $\varepsilon > 0$, as $n$ tends to infinity, $Pr\left[G(n, (1-\varepsilon)\widehat c/\sqrt{n}) \in \cal{R} \right] \rightarrow 0$ and $Pr \left[ G(n, (1]\varepsilon)\widehat c/\sqrt{n}) \in \cal{R}\ \right] \rightarrow 1.$. A crucial tool that is used in the proof and is of independent interest is a generalization of Szemeredi's Regularity Lemma to a certain hypergraph setti

Semisolvability of Semisimple Hopf Algebras of Low Dimension

Semisolvability of Semisimple Hopf Algebras of Low Dimension
Author: Sonia Natale
Publisher: American Mathematical Soc.
Total Pages: 138
Release: 2007
Genre: Mathematics
ISBN: 0821839489

The author proves that every semisimple Hopf algebra of dimension less than $60$ over an algebraically closed field $k$ of characteristic zero is either upper or lower semisolvable up to a cocycle twist.

Casimir Force, Casimir Operators and the Riemann Hypothesis

Casimir Force, Casimir Operators and the Riemann Hypothesis
Author: Gerrit van Dijk
Publisher: Walter de Gruyter
Total Pages: 295
Release: 2010
Genre: Business & Economics
ISBN: 311022612X

The series is aimed specifically at publishing peer reviewed reviews and contributions presented at workshops and conferences. Each volume is associated with a particular conference, symposium or workshop. These events cover various topics within pure and applied mathematics and provide up-to-date coverage of new developments, methods and applications.

Matching Theory

Matching Theory
Author: László Lovász
Publisher: American Mathematical Soc.
Total Pages: 610
Release: 2009
Genre: Mathematics
ISBN: 0821847597

This book surveys matching theory, with an emphasis on connections with other areas of mathematics and on the role matching theory has played, and continues to play, in the development of some of these areas. Besides basic results on the existence of matchings and on the matching structure of graphs, the impact of matching theory is discussed by providing crucial special cases and nontrivial examples on matroid theory, algorithms, and polyhedral combinatorics. The new Appendix outlines how the theory and applications of matching theory have continued to develop since the book was first published in 1986, by launching (among other things) the Markov Chain Monte Carlo method.

KAM Stability and Celestial Mechanics

KAM Stability and Celestial Mechanics
Author: Alessandra Celletti
Publisher: American Mathematical Soc.
Total Pages: 150
Release: 2007
Genre: Mathematics
ISBN: 0821841696

KAM theory is a powerful tool apt to prove perpetual stability in Hamiltonian systems, which are a perturbation of integrable ones. The smallness requirements for its applicability are well known to be extremely stringent. A long standing problem, in this context, is the application of KAM theory to ``physical systems'' for ``observable'' values of the perturbation parameters. The authors consider the Restricted, Circular, Planar, Three-Body Problem (RCP3BP), i.e., the problem of studying the planar motions of a small body subject to the gravitational attraction of two primary bodies revolving on circular Keplerian orbits (which are assumed not to be influenced by the small body). When the mass ratio of the two primary bodies is small, the RCP3BP is described by a nearly-integrable Hamiltonian system with two degrees of freedom; in a region of phase space corresponding to nearly elliptical motions with non-small eccentricities, the system is well described by Delaunay variables. The Sun-Jupiter observed motion is nearly circular and an asteroid of the Asteroidal belt may be assumed not to influence the Sun-Jupiter motion. The Jupiter-Sun mass ratio is slightly less than 1/1000. The authors consider the motion of the asteroid 12 Victoria taking into account only the Sun-Jupiter gravitational attraction regarding such a system as a prototype of a RCP3BP. for values of mass ratios up to 1/1000, they prove the existence of two-dimensional KAM tori on a fixed three-dimensional energy level corresponding to the observed energy of the Sun-Jupiter-Victoria system. Such tori trap the evolution of phase points ``close'' to the observed physical data of the Sun-Jupiter-Victoria system. As a consequence, in the RCP3BP description, the motion of Victoria is proven to be forever close to an elliptical motion. The proof is based on: 1) a new iso-energetic KAM theory; 2) an algorithm for computing iso-energetic, approximate Lindstedt series; 3) a computer-aided application of 1)+2) to the Sun-Jupiter-Victoria system. The paper is self-contained but does not include the ($\sim$ 12000 lines) computer programs, which may be obtained by sending an e-mail to one of the authors.