On proving the equivalence of concurrency primitives

Various concurrency primitives have been added to sequential programming languages, in order to turn them concurrent. Prominent examples are concurrent buffers for Haskell, channels in Concurrent ML, joins in JoCaml, and handled futures in Alice ML. Even though one might conjecture that all these primitives provide the same expressiveness, proving this equivalence is an open challenge in the area of program semantics. In this paper, we establish a first instance of this conjecture. We show that concurrent buffers can be encoded in the lambda calculus with futures underlying Alice ML. Our correctness proof results from a systematic method, based on observational semantics with respect to may and must convergence

Managing Cultural Diversity in the Multinational Corporate Workplace: Solution or Symptom?

The aim of this paper is to show the critical relevance of post-structuralist political theory to cross-cultural management studies. By emphasizing the key role that questions of identity, difference, and struggle play in the multinational corporate context, we argue for a shift in our understandings away from essentialist conceptions of culture to an explicitly critical and political understanding of the way culture and cultural difference is invoked. Of crucial importance in understanding the nature of the shift of perspective we advocate is the affirmation of a negative ontology for which the radical contingency of social relations is axiomatic

Petri Nets and Other Models of Concurrency

This paper retraces, collects, and summarises contributions of the authors --- in collaboration with others --- on the theme of Petri nets and their categorical relationships to other models of concurrency

A Tracing Method for Pricing Inter-Area Electricity Trades

In the context of liberalisation of electricity markets world wide, the need for agreed protocols for electricity trades between systems with different charges poses a special challenge. System operators need to know how much a given trade uses the network, in order to allocate an appropriate portion of their costs to that trade. This paper discusses a technique, tracing, for determining how much each of a number of trades uses different parts of the electricity network. The scheme is based on the assumption that at any network node, inflows are shared proportionally between outflows (and vice versa). The paper outlines the technique and shows how it could be applied to the problem of charging cross-border trades. The paper goes on to demonstrate that the technique has a game theoretic rationale, in that it produces the Shapley value solution to a game equivalent to this allocation problem

Strategic Power Revisited

Traditional power indices ignore preferences and strategic interaction. Equilibrium analysis of particular non-cooperative decision procedures is unsuitable for normative analysis and assumes typically unavailable information. These points drive a lingering debate about the right approach to power analysis. A unified framework that works both sides of the street is developed here. It rests on a notion of a posteriori power which formalizes players' marginal impact to outcomes in cooperative and non-cooperative games, for strategic interaction and purely random behaviour. Taking expectations with respect to preferences, actions, and procedures then defines a meaningful a priori measure. Established indices turn out to be special cases.power indices, spatial voting, equilibrium analysis, decision procedures

Peirce, meaning and the semantic web

The so-called ‘Semantic Web’ is phase II of Tim Berners-Lee’s original vision for the WWW, whereby resources would no longer be indexed merely ‘syntactically’, via opaque character-strings, but via their meanings. We argue that one roadblock to Semantic Web development has been researchers’ adherence to a Cartesian, ‘private’ account of meaning, which has been dominant for the last 400 years, and which understands the meanings of signs as what their producers intend them to mean. It thus strives to build ‘silos of meaning’ which explicitly and antecedently determine what signs on the Web will mean in all possible situations. By contrast, the field is moving forward insofar as it embraces Peirce’s ‘public’, evolutionary account of meaning, according to which the meaning of signs just is the way they are interpreted and used to produce further signs. Given the extreme interconnectivity of the Web, it is argued that silos of meaning are unnecessary as plentiful machine-understandable data about the meaning of Web resources exists already in the form of those resources themselves, for applications that are able to leverage it, and it is Peirce’s account of meaning which can best make sense of the recent explosion in ‘user-defined content’ on the Web, and its relevance to achieving Semantic Web goals

Clock and Category; IS QUANTUM GRAVITY ALGEBRAIC

We investigate the possibility that the quantum theory of gravity could be constructed discretely using algebraic methods. The algebraic tools are similar to ones used in constructing topological quantum field theories.The algebraic tools are related to ideas about the reinterpretation of quantum mechanics in a general relativistic context.Comment: To appear in special issue of JMP. Latex documen