Iterated spans and classical topological field theories

We construct higher categories of iterated spans, possibly equipped with extra structure in the form of "local systems", and classify their fully dualizable objects. By the Cobordism Hypothesis, these give rise to framed topological quantum field theories, which are the framed versions of the "classical" TQFTs considered in the quantization programme of Freed-Hopkins-Lurie-Teleman. Using this machinery, we also construct an infinity-category of Lagrangian correspondences between symplectic derived algebraic stacks and show that all its objects are fully dualizable.Comment: Accepted version, plus corrections to Remarks 10.5 and 10.7. 64 page

On the Structure of Covers of Sofic Shifts

A canonical cover generalizing the left Fischer cover to arbitrary sofic shifts is introduced and used to prove that the left Krieger cover and the past set cover of a sofic shift can be divided into natural layers. These results are used to find the range of a flow-invariant and to investigate the ideal structure of the universal C*-algebra associated to a sofic shift space.Comment: To appear in Documenta Mathematica. Section 2 has been shortened. Three sections concerning the layered structure of the left Krieger cover and the past set cover have been merged and rewritten. Non-essential examples have been omitted. 21 pages, 8 figure

Segal spaces, spans, and semicategories

We show that Segal spaces, and more generally category objects in an $\infty$-category $\mathcal{C}$, can be identified with associative algebras in the double $\infty$-category of spans in $\mathcal{C}$. We use this observation to prove that "having identities" is a property of a non-unital $(\infty,n)$-category.Comment: Accepted version, 14 page

Life and death in wolverines

Developing trustworthy conservation planning for endangered species requires a deep understanding of the variations of their populations in both space and time. I used individual-based long-term location and demographic data on wolverines (Gulo gulo) in Northern Sweden, and data on reproductions from the national monitoring systems of Norway and Sweden, to analyze how wolverine demography in Scandinavia is affected by variation in habitat and management policies. Wolverines showed agerelated patterns of reproduction and reproductive costs, which were influenced by seasonal resources. The top predator Eurasian lynx (Lynx lynx) increase scavenging opportunities on reindeer (Rangifer tarandus) carrion, and wolverines and lynx selected for the same habitats when sharing prey base and sources of adult mortality. Illegal killing was a main source of adult mortality in brown bears (Ursus arctos), lynx and wolverines in northern Sweden, and the risk of being illegally killed was in general higher in national parks and on reindeer calving grounds, and lower in forest and steep terrain. At population level, the reproductive range of wolverines was set by latitude and elevation; presence of reindeer and lynx, rugged terrain and higher primary production had a positive effect; whereas human dominated habitats negatively influenced the frequency of reproductions. Different management policies influenced the frequency of wolverine reproductions; in Sweden this was 2 times higher than in Norway. Finally, I show that in Sweden, adult female wolverines were illegally killed at lower rates than males. Thus, the Swedish carnivore conservation payment system, which pays for wolverine reproductions, protects the demographic segment that is most important for population growth. Carnivores impose negative impact on rural economies and herding cultures in Scandinavia, and there will be need for continued monitoring combined with economic incentives to ensure carnivore-human coexistence. The approach of linking life histories to habitat has the potential for in-depth studies of mechanisms shaping spatial and temporal variation in populations, and should be implemented in future adaptive management for species persistence

Aftershock: Reflections on the Politics of Reconstruction in Northern Gorkha

Many commentators have described the aftermath of the 2015 earthquake in Nepal either (1) through the notion that ‘nothing is going on’ in regards to postquake reconstruction; or (2) through a celebration of grassroots resilience and urban entrepreneurship in the face of disaster and state neglect. In this article, I draw on observations from Kutang and Nubri in the mountains of northern Gorkha District to argue that neither of these descriptions is fully accurate. Even in this remote and inaccessible area, much was being done in the aftermath of disaster, and a great deal of this activity diverges, in multiple ways, from the notions of spontaneous egalitarianism that are often associated with ‘resilience.’ I describe the fraught politics involved in distributing relief aid in a village where the local government has been non-existent for years; the active positioning of new political players on the local scene; and the economic inequalities that can arise from unlucky positioning along geological fault-lines, a recently booming tourist economy, and the specificities of the Nepali government’s post-disaster compensation schemes. This article sketches out the anatomy of disaster ‘aftershock’ as a political environment rife with opportunity, bias, and unintended consequences. As scholars and interested observers of Nepal and the Himalaya, we need to pay close attention to this environment and its potentially unequal outcomes that reverberate past this present moment of taking stock