Corrigendum to “A Schanuel Condition for Weierstrass Equations”

I prove a version of Schanuel's conjecture for Weierstrass equations in differential fields, answering a question of Zilber, and show that the linear independence condition in the statement cannot be relaxed

Efficient Compilation of a Class of Variational Forms

We investigate the compilation of general multilinear variational forms over affines simplices and prove a representation theorem for the representation of the element tensor (element stiffness matrix) as the contraction of a constant reference tensor and a geometry tensor that accounts for geometry and variable coefficients. Based on this representation theorem, we design an algorithm for efficient pretabulation of the reference tensor. The new algorithm has been implemented in the FEniCS Form Compiler (FFC) and improves on a previous loop-based implementation by several orders of magnitude, thus shortening compile-times and development cycles for users of FFC.Comment: ACM Transactions on Mathematical Software 33(3), 20 pages (2007

Gadamer, Dewey, and the importance of play in philosophical inquiry

Over the last eighty years, studies in play have carved out a small, but increasingly significant, niche within the social sciences and a rich repository has been built which underscores the importance of play to social, cultural, and psychological development. The general point running through these works is a philosophical recognition that play should not be separated from the trappings of everyday life, but instead should be seen as one of the more primordial aspects of human existence. Gadamer is one philosopher frequently associated with interest in play. In his magnum opus, Truth and Method (1960), Gadamer insisted the significance of play to human understanding is not merely recreational, but rather it discloses the full context of any given situation by promoting a freedom of possibilities within the horizon of one’s own life-world (i.e. the world directly and immediately experienced). As such, his philosophical analysis of play was essential to his overall project of philosophical hermeneutics as it can explain how meaning is not derived from something essential within a text, but rather considered from a full range of possibilities. There are good reasons to expand on that understanding of play within philosophical studies and we suggest one way to do so is to compare Gadamer’s treatment of play with similar ideas from thinkers often associated with other philosophical schools. Although there are other candidates (e.g. Wittgenstein’s language games) for such an analysis, we limit our comparison here to the notion of transaction, as treated by the American pragmatist John Dewey in his volume Knowing and the Known (co-authored with Arthur Bentley in 1949). Because Dewey tied his conception of transaction to an overarching philosophy of inquiry, we believe comparing it to Gadamer’s use of play can highlight the deep philosophical import of this concept to the understanding of philosophical inquiry

A note on the axioms for Zilber's pseudo-exponential fields

We show that Zilber's conjecture that complex exponentiation is isomorphic to his pseudo-exponentiation follows from the a priori simpler conjecture that they are elementarily equivalent. An analysis of the first-order types in pseudo-exponentiation leads to a description of the elementary embeddings, and the result that pseudo-exponential fields are precisely the models of their common first-order theory which are atomic over exponential transcendence bases. We also show that the class of all pseudo-exponential fields is an example of a non-finitary abstract elementary class, answering a question of Kes\"al\"a and Baldwin.Comment: 10 pages, v2: substantial alteration

The Peak

This paper won a third place writing flag award in the creative/reflective category. Kensey Kirby, writing for Greg Curtis’s LAH 350 class, “Writing Non-Fiction”.Curtis, GregUndergraduate Studie

Refusing to be a man?: Men's responsibility for war rape and the problem of social structures in feminist and gender theory

As the majority perpetrators of sexual violence, it is plausible to see men as responsible for war rape not only as individuals, but also as collective bystanders, facilitators and beneficiaries. Following recent criticisms of individual legal and moral responsibility for rape as a war crime in international law, this article examines how we might think of war rape as a collective action in moral and sociological terms. First, it assesses existing moral arguments for the responsibility of men in groups for rape, primarily with reference to the work of Claudia Card, Larry May and Robert Strikwerda. Critiquing elements of these arguments, it explores the difficulties in talking about ‘men’ as a coherent group and in discussing ‘collectives’ themselves. Second, the article draws out the connection between accounts of moral responsibility and accounts of causal responsibility. Drawing on critiques of collective responsibility and the long-standing agency/structure problem, it argues that causal accounts focusing on structure pose a serious challenge to ideas of both individual and collective moral responsibility. The complexities of the relationship between moral and causal claims are illustrated through a discussion of Susan Brownmiller and Catharine MacKinnon’s influential perspectives on rape. The seeming paradox of responsibility is emphasised as a problem to be addressed by gender and feminist perspectives that seek to pursue both ethical and sociological inquiry into the workings of masculinity and the political means for undoing gendered wrongs

Partial Matrix Techniques.

Partial matrix techniques are those in which gravity models are fitted to a partially observed matrix of trips and journey costs, and used to infer the trips in the unobserved cells. This paper reviews the theoretical basis from which such techniques have been developed, and demonstrates the need to pay careful attention to the - underlying assumptions, which in effect require that the model be a good fit to be observed data (and also a good 'fit' to the unobserved data). Circumstances are described in which the estimates for the unobserved cells may not be uniquely determined, and the effects of data structure on the reliability of the estimates (assuming these to be unique) are discussed. Ways are suggested in which further theoretical and empirical research might demonstrate whether a given pattern of observations would lead to particularly error-prone estimates

The rational field is not universally definable in pseudo-exponentiation

We show that the field of rational numbers is not definable by a universal formula in Zilber's pseudo-exponential field

How Can Speech Recognisers Help Applied Research in the Civil Engineering, Transport and Related Industries

BACKGROUND Speech recognition technology is rapidly advancing to the point here it can be usefully applied in a wide range of mtexts. For applications within the SERC Environment Committee's area of interest -civil engineering; construction; building; transport; water resources there are a number of kinds of recording situation in which one needs to keep one's eyes on the situation being studied; or in which the recording conditions (eg moving around with instruments) are unfavourable. The limitations of conventional pen and paper recording for these situations are obvious; and the limitations of hand-held data capture devices are also becoming apparent. Speech is therefore an easier medium to use; and a tape recorder a convenient means of recording the observations. For well defined recording tasks; speech recognisers might be a helpful way of transcribing the record. This seminar was convened to enable those who are potentially interested in such an application of information technology to hear of the latest developnents and assessments of the suitability of the technology

Report on the Workshop held at the University of Leeds on 6 November organised on behalf of the Transport Sub-Committee of the Environment Committee of the Science and Engineering Research Council

The meeting was the second in a series of three; called to review the prospects for future development of the Special Programme in the Application of Information Technology to Transport set up by the Transport Sub-committee of the Science and Engineering Research Council (SERC). The other seminars were: at University College London on Traffic Engineering Applications; held in July 1986; and at the University of Newcastle up Tyne, on Public Transport Information Systems, held in December 1986. The objectives of the workshop were to (i) review current perceptions of and future prospects for the role of expert systems in transport; and (ii) provide such feed-back to the SERC Transport Sub-committee as would assist it in forming a view about future work in this area. (Continues..