Moduli spaces of torsion sheaves on K3 surfaces and derived equivalences

We show that for many moduli spaces M of torsion sheaves on K3 surfaces S, the functor D(S) -> D(M) induced by the universal sheaf is a P-functor, hence can be used to construct an autoequivalence of D(M), and that this autoequivalence can be factored into geometrically meaningful equivalences associated to abelian fibrations and Mukai flops. Along the way we produce a derived equivalence between two compact hyperkaehler 2g-folds that are not birational, for every g >= 2. We also speculate about an approach to showing that birational moduli spaces of sheaves on K3 surfaces are derived-equivalent.Comment: 28 pages. typos corrected. final version to appear in JLM

Gendered landscapes of safety : how women construct and navigate the urban landscape to avoid sexual violence.

This article presents findings from an online survey gathering quantitative and qualitative data from men and women students at a university in the north of England in 2016. The survey explored their perceptions of safety and experiences of interpersonal violence during their time as a student, both on and off campus. We show how women were more likely to report sexual violence compared to men. We also show how women students, compared to men, were less likely to say they never felt unsafe as they moved away from the university into the city, and as they moved from day into night. We illustrate how interconnecting factors construct women’s perceptions of safety, and subsequently, how locations perceived as unsafe ‘hotspots’, become physical barriers impeding women’s access to public and educational spaces. Consequently, we outline measures to enhance women’s safety whilst at university

Drivers in solar deployment in India: A state-level analysis

This report considers the drivers of inter-state solar power deployment in India, and what mix of policies are most appropriate to help India reach its ambitious solar power target

Convective activity in a Martian magma chamber recorded by P-zoning in Tissint olivine

The Tissint Martian meteorite is an unusual depleted olivine‐phyric shergottite, reportedly sourced from a mantle‐derived melt within a deep magma chamber. Here, we report major and trace element data for Tissint olivine and pyroxene, and use these data to provide new insights into the dynamics of the Tissint magma chamber. The presence of irregularly spaced oscillatory phosphorous (P)‐rich bands in olivine, along with geochemical evidence indicative of a closed magmatic system, implies that the olivine grains were subject to solute trapping caused by vigorous crystal convection within the Tissint magma chamber. Calculated equilibration temperatures for the earliest crystallizing (antecrystic) olivine cores suggest a Tissint magma source temperature of 1680 °C, and a local Martian mantle temperature of 1560 °C during the late Amazonian—the latter being consistent with the ambient mantle temperature of Archean Earth

Beyond mystery: Putting algorithmic accountability in context

Critical algorithm scholarship has demonstrated the difficulties of attributing accountability for the actions and effects of algorithmic systems. In this commentary, we argue that we cannot stop at denouncing the lack of accountability for algorithms and their effects but must engage the broader systems and distributed agencies that algorithmic systems exist within; including standards, regulations, technologies, and social relations. To this end, we explore accountability in “the Generated Detective,” an algorithmically generated comic. Taking up the mantle of detectives ourselves, we investigate accountability in relation to this piece of experimental fiction. We problematize efforts to effect accountability through transparency by undertaking a simple operation: asking for permission to re-publish a set of the algorithmically selected and modified words and images which make the frames of the comic. Recounting this process, we demonstrate slippage between the “complication” of the algorithm and the obscurity of the legal and institutional structures in which it exists