Transport Networks Revisited: Why Dual Graphs?

Deterministic equilibrium flows in transport networks can be investigated by means of Markov's processes defined on the dual graph representations of the network. Sustained movement patterns are generated by a subset of automorphisms of the graph spanning the spatial network of a city naturally interpreted as random walks. Random walks assign absolute scores to all nodes of a graph and embed space syntax into Euclidean space.Comment: 12 page

The Network Analysis of Urban Streets: A Primal Approach

The network metaphor in the analysis of urban and territorial cases has a long tradition especially in transportation/land-use planning and economic geography. More recently, urban design has brought its contribution by means of the "space syntax" methodology. All these approaches, though under different terms like accessibility, proximity, integration,connectivity, cost or effort, focus on the idea that some places (or streets) are more important than others because they are more central. The study of centrality in complex systems,however, originated in other scientific areas, namely in structural sociology, well before its use in urban studies; moreover, as a structural property of the system, centrality has never been extensively investigated metrically in geographic networks as it has been topologically in a wide range of other relational networks like social, biological or technological. After two previous works on some structural properties of the dual and primal graph representations of urban street networks (Porta et al. cond-mat/0411241; Crucitti et al. physics/0504163), in this paper we provide an in-depth investigation of centrality in the primal approach as compared to the dual one, with a special focus on potentials for urban design.Comment: 19 page, 4 figures. Paper related to the paper "The Network Analysis of Urban Streets: A Dual Approach" cond-mat/041124

The global existence and convergence of the Calabi flow on Cn/Zn+iZn\mathbb{C}^n/\mathbb{Z}^n + i\mathbb{Z}^n

In this note, we study the long time existence of the Calabi flow on $X = \mathbb{C}^n/\mathbb{Z}^n + i\mathbb{Z}^n$. Assuming the uniform bound of the total energy, we establish the non-collapsing property of the Calabi flow by using Donaldson's estimates and Streets' regularity theorem. Next we show that the curvature is uniformly bounded along the Calabi flow on $X$ when the dimension is 2, partially confirming Chen's conjecture. Moreover, we show that the Calabi flow exponentially converges to the flat K\"ahler metric for arbitrary dimension if the curvature is uniformly bounded, partially confirming Donaldson's conjecture

How actors move from primary agency to institutional agency: A conceptual framework and empirical application

This article contributes to the understanding of actors and agency in the theorization of institutional work. We analyse institutional work as a specific kind of social action that involves exercising institutional agency (with an articulate awareness of institutions) as opposed to primary agency (taking institutions for granted). We propose a conceptual framework for combining a view of actors, who have agency and may engage in institutional work, with a view of actors as socially constructed, in line with critical-realist ontology. Applying this framework to the empirical case of the Spanish social movement 15M, we examine how actors moved from having primary agency to having institutional agency and how organization mattered for this process. We find that organizing by experienced organizers, the founding of new organizations and prefigurative organization were of crucial importance for the increase in institutional agency

Playing with tension:national charisma and disgrace at Euro 2012

By the time of Euro 2012, deepening tensions of nationalism and internal social struggles were developing across Europe in worsening conditions of systemic crisis. The official football ideology of UEFA conceives Euro 2012 as a civilizing platform for mutual respect and brotherhood between competing nations. In contrast, what I call Hyper-Critical Theory conceives of football competitions like Euro 2012 as part of a de-civilising ‘sports mode of production’ that necessarily produces crisis conditions, alienation and violence on a mass scale, fostering nationalism, militarism and racism. Between these polar perspectives, the figurational sociology of sport associated with Norbert Elias proposes that major international football competitions like Euro 2012 creates and dissipates contingent tensions of ‘group charisma’ and ‘group disgrace’. Study of Euronews ‘post-national’ coverage of Euro 2012 allows their explanatory adequacy to be compared. In a competition structure like the Euros no social group – players, officials, media or fans – is able to disregard entirely the field capabilities of the ‘best minority of 11’ in the serious game of exemplifying the group charisma of nations

A Stationary, Mixing and Perturbative Counterexample to the 0-1-law for Random Walk in Random Environment in Two Dimensions

We construct a two-dimensional counterexample of a random walk in random environment (RWRE). The environment is stationary, mixing and perturbative, and the corresponding RWRE has non-trivial probability to wander off to the upper right. This is in contrast to the 0-1-law that holds for i.i.d.\ environments