Symplectic torus bundles and group extensions

Symplectic torus bundles $\xi:T^{2}\to E\to B$ are classified by the second cohomology group of $B$ with local coefficients $H_{1}(T^{2})$. For $B$ a compact, orientable surface, the main theorem of this paper gives a necessary and sufficient condition on the cohomology class corresponding to $\xi$ for $E$ to admit a symplectic structure compatible with the symplectic bundle structure of $\xi$ : namely, that it be a torsion class. The proof is based on a group-extension-theoretic construction of J. Huebschmann (Sur les premieres differentielles de la suite spectrale cohomologique d'une extension de groupes, C.R. Acad. Sc. Paris, Serie A, tome 285, 28 novembre 1977, 929-931). A key ingredient is the notion of fibrewise-localization.Comment: 18 page

Kant’s theory of conscience

In this paper I discuss Kant’s theory of conscience. In particular, I explicate the following two claims that Kant makes in the Metaphysics of Morals: (1) an erring conscience is an absurdity and (2) if an agent has acted according to his/her conscience, then s/he has done all that can be required of him/her. I argue that (1) is a very specific claim that does not bear on the problem of moral knowledge. I argue that (2) rests on a strongly internalist line of argument

California Voting and Suburbanization Patterns: Implications for Transit Policy, MTI Report 12-05

Public transit is an environmentally friendly transportation mode that usually focuses on transporting people within and to the city center. However, over the last 60 years, population and employment has been suburbanizing. As the median voter lives further from the city center, and thus enjoys fewer benefits from accessing public transit, does this reduce such a voter’s propensity to support public investment in public transit improvements? We analyze voting patterns on 20 transit-related ballot propositions from state-wide elections in California between 1990 and 2010. Controlling for demographic, socio-economic and political ideological factors, we focus on the role of suburbanization as a possible causal factor in determining public support for public transit investment. The results provide a rich picture of the attitudes towards transportation policy among California voters, and will help policy makers to better understand citizen preferences and to better predict how future trends will shift support towards or against transit. Finally, we suggest ways policy makers can use urban land markets to increase support for trans

The Impact of Center City Economic and Cultural Vibrancy on Greenhouse Gas Emissions from Transportation, Research Report 11-13

Urban planners and scholars have focused a great deal of attention on understanding the relationship between the built environment and transportation behavior. However, other aspects of the urban environment – including the vibrancy and quality of life in urban areas – have received little attention. This report seeks to close this gap by analyzing the effects of both land-use and urban vibrancy on transportation patterns. Analysis of data from a variety of sources suggests that in addition to the built-environment, the vibrancy of the urban environment also affects transportation behavior. Moreover, vibrancy affects land-use patterns. By integrating objective measures of center-city quality of life into transportation choice models, our new statistical results inform public policy. We discuss specific public policy options for reducing greenhouse gas emissions and increasing public transit use

Proof of a conjecture of N. Konno for the 1D contact process

Consider the one-dimensional contact process. About ten years ago, N. Konno stated the conjecture that, for all positive integers $n,m$, the upper invariant measure has the following property: Conditioned on the event that $O$ is infected, the events $\{$All sites $-n,...,-1$ are healthy$\}$ and $\{$All sites $1,...,m$ are healthy$\}$ are negatively correlated. We prove (a stronger version of) this conjecture, and explain that in some sense it is a dual version of the planar case of one of our results in \citeBHK.Comment: Published at http://dx.doi.org/10.1214/074921706000000031 in the IMS Lecture Notes--Monograph Series (http://www.imstat.org/publications/lecnotes.htm) by the Institute of Mathematical Statistics (http://www.imstat.org