Trace Substances, Science and Law: Perspectives from the Social Sciences

Using advances in analytical technology as a point of departure, Dr. Short reviews what social science research reveals about perceptions, decision making processes and behaviors of organizations and individuals who try to cope with risk and uncertainty

Erving Seemed Surprised at How Little “Power” Came with the ASA Presidency, and Noted that the Position of Secretary Carried Much More Clout

Dr. James F. Short, Professor Emeritus at the Washington State University, wrote this memoir at the request of Dmitri Shalin and gave his permission to post it in the Erving Goffman Archives

On the finite presentation of subdirect products and the nature of residually free groups

We establish {\em{virtual surjection to pairs}} (VSP) as a general criterion for the finite presentability of subdirect products of groups: if $\Gamma_1,...,\Gamma_n$ are finitely presented and $S<\Gamma_1\times...\times\Gamma_n$ projects to a subgroup of finite index in each $\Gamma_i\times\Gamma_j$, then $S$ is finitely presentable, indeed there is an algorithm that will construct a finite presentation for $S$. We use the VSP criterion to characterise the finitely presented residually free groups. We prove that the class of such groups is recursively enumerable. We describe an algorithm that, given a finite presentation of a residually free group, constructs a canonical embedding into a direct product of finitely many limit groups. We solve the (multiple) conjugacy problem and membership problem for finitely presentable subgroups of residually free groups. We also prove that there is an algorithm that, given a finite generating set for such a subgroup, will construct a finite presentation. New families of subdirect products of free groups are constructed, including the first examples of finitely presented subgroups that are neither ${\rm{FP}}_\infty$ nor of Stallings-Bieri typeComment: 44 pages. To appear in American Journal of Mathematics. This is a substantial rewrite of our previous Arxiv article 0809.3704, taking into account subsequent developments, advice of colleagues and referee's comment

Finitely presented subgroups of automatic groups and their isoperimetric functions

We describe a general technique for embedding certain amalgamated products into direct products. This technique provides us with a way of constructing a host of finitely presented subgroups of automatic groups which are not even asynchronously automatic. We can also arrange that such subgroups satisfy, at best, an exponential isoperimetric inequality.Comment: DVI and Post-Script files only. To appear in J. London Math. So

Subgroups of direct products of limit groups

If $G_1,...,G_n$ are limit groups and $S\subset G_1\times...\times G_n$ is of type \FP_n(\mathbb Q) then $S$ contains a subgroup of finite index that is itself a direct product of at most $n$ limit groups. This settles a question of Sela.Comment: 20 pages, no figures. Final version. Accepted by the Annals of Mathematic

Hell as the Here-and-Now

HELL AS THE HERE-AND-NOW: IMAGES OF HUMAN TRAVAIL IN TWELFTH-CENTURY EMAKI AND KUROSAWA'S RANAKIRA KUROSAWA'S last major epic film, Ran (translatable as "chaos"), begins in media res with the moment of precipitous decline of the seventy-year-old Hidetora, a medieval-period daimyo. Hidetora gathers together his three sons and two lesser daimyo, lords Fujimaki and Ayabe, for first a hunt, then to issue an edict: Though he will retain his banner and ceremonial title of Great Lord, his oldest son, Taro, will henceforth act as the clan's leader. Hidetora hopes to spend his remaining years as a doting and beloved father. But, as Hidetora's son Saburo warns, such familial peace and bliss is hardly achievable within a world of warriors and their competing ambitions, a world that Hidetora himself helped to create through his many ruthless acts. This meeting of hunter-warriors is both sequel to the violent episodes in..

Cryptanalyzing a discrete-time chaos synchronization secure communication system

This paper describes the security weakness of a recently proposed secure communication method based on discrete-time chaos synchronization. We show that the security is compromised even without precise knowledge of the chaotic system used. We also make many suggestions to improve its security in future versions.Comment: 11 pages, 3 figures, latex forma