Residual generic ergodicity of periodic group extensions over translation surfaces

Continuing the work in \cite{ergodic-infinite}, we show that within each stratum of translation surfaces, there is a residual set of surfaces for which the geodesic flow in almost every direction is ergodic for almost-every periodic group extension produced using a technique referred to as \emph{cuts}

ω\omega-recurrence in cocycles

After relating the notion of $\omega$-recurrence in skew products to the range of values taken by partial ergodic sums and Lyapunov exponents, ergodic $\mathbb{Z}$-valued cocycles over an irrational rotation are presented in detail. First, the generic situation is studied and shown to be $1/n$-recurrent. It is then shown that for any $\omega(n) <n^{-\epsilon}$, where $\epsilon>1/2$, there are uncountably many infinite staircases (a certain specific cocycle over a rotation) which are \textit{not} $\omega$-recurrent, and therefore have positive Lyapunov exponent. A further section makes brief remarks regarding cocycles over interval exchange transformations of periodic type

The French Military and the Problem of Twentieth Century War

The technological and social changes that have overtaken and outdated the traditionally autonomous role of the military in society have nowhere had more serious ramifications than in the Army of France

Climate Action Planning and Urban Greenways: Weaving Together Sustainability, Health and Resilience

Envisioning and planning citywide greenways and supporting urban greening (green infrastructure) linked to climate action planning are surprisingly not well integrated in sustainable planning initiatives and in fact represent two separate landscape action approaches and two different scales and disciplines of focus. By not being strategically integrated, cities are missing out on many significant environmental and social co-benefits that are especially needed at this time. Consider, the planning focus for greenways (especially in the US context) over the last forty-years has generally emerged from a landscape design and park planning tradition and thus we see various inter-city/regional or suburban “pleasure way” or neo-“garden city” features typically centered on landscaped Class I bicycle and walking pathway as part of reclaiming or reinvesting in post-industrial urban spaces along waterways and railroad tracks.1 Meanwhile, on a very independent trajectory over the last two decades, green infrastructure planning – usually conceived as place-specific features to recapture storm-water or provide needed vegetative greening or other energy savings has been getting increasing attention as a retrofit method for improving urban ecological health (Beatley, 2014). Greenways are more than just one conceptual thing such as a linear parks but a connecting fabric or more appropriately the urban green infrastructure that can and should be woven in to retrofit the city and provide support where it is most needed and make the city more livable by introducing bands and groves of tree canopy, fresh air, access to nature, connection to unique ecological features, open-up view corridors, provide places for outdoor exercise; support local urban agriculture, offer flood protection; provide pedestrian-scale networks for socializing and non-motorized cross-city access; and, least appreciated of all, become places of cultural expression