Anatomy of a Conference Twitter Hashtag: #AALL2010

Written as a the Tech Talk column for Law Library Lights, this brief article summarizes conference Twitter posts for the American Association of Law Libraries 2010 conference, held in Denver, Colorado. The Twitter content analyzed in the article is available to download from this site as an Excel file or a .tar archive

Deforming the Lie algebra of vector fields on S1S^1 inside the Poisson algebra on T˙∗S1\dot T^*S^1

We study deformations of the standard embedding of the Lie algebra \Vect(S^1) of smooth vector fields on the circle, into the Lie algebra of functions on the cotangent bundle $T^*S^1$ (with respect to the Poisson bracket). We consider two analogous but different problems: (a) formal deformations of the standard embedding of \Vect(S^1) into the Lie algebra of functions on \dot T^*S^1:=T^*S^1\setminusS^1 which are Laurent polynomials on fibers, and (b) polynomial deformations of the \Vect(S^1) subalgebra inside the Lie algebra of formal Laurent series on $\dot T^*S^1$.Comment: 19 pages, LaTe

Pfaffian formulae for one dimensional coalescing and annihilating systems

The paper considers instantly coalescing, or instantly annihilating, systems of one-dimensional Brownian particles on the real line. Under maximal entrance laws, the distribution of the particles at a fixed time is shown to be Pfaffian point processes closely related to the Pfaffian point process describing one dimensional distribution of real eigenvalues in the real Ginibre ensemble of random matrices. As an application, an exact large time asymptotic for the n-point density function for coalescing particles is derived

Efficient management of backtracking in and-parallelism

A backtracking algorithm for AND-Parallelism and its implementation at the Abstract Machine level are presented: first, a class of AND-Parallelism models based on goal independence is defined, and a generalized version of Restricted AND-Parallelism (RAP) introduced as characteristic of this class. A simple and efficient backtracking algorithm for R A P is then discussed. An implementation scheme is presented for this algorithm which offers minimum overhead, while retaining the performance and storage economy of sequent ial implementations and taking advantage of goal independence to avoid unnecessary backtracking ("restricted intelligent backtracking"). Finally, the implementation of backtracking in sequential and AND-Parallcl systems is explained through a number of examples

Representations of quivers and mixed graphs

This is a survey article for "Handbook of Linear Algebra", 2nd ed., Chapman & Hall/CRC, 2014. An informal introduction to representations of quivers and finite dimensional algebras from a linear algebraist's point of view is given. The notion of quiver representations is extended to representations of mixed graphs, which permits one to study systems of linear mappings and bilinear or sesquilinear forms. The problem of classifying such systems is reduced to the problem of classifying systems of linear mappings