Orders of accumulation of entropy

For a continuous map $T$ of a compact metrizable space $X$ with finite topological entropy, the order of accumulation of entropy of $T$ is a countable ordinal that arises in the context of entropy structure and symbolic extensions. We show that every countable ordinal is realized as the order of accumulation of some dynamical system. Our proof relies on functional analysis of metrizable Choquet simplices and a realization theorem of Downarowicz and Serafin. Further, if $M$ is a metrizable Choquet simplex, we bound the ordinals that appear as the order of accumulation of entropy of a dynamical system whose simplex of invariant measures is affinely homeomorphic to $M$. These bounds are given in terms of the Cantor-Bendixson rank of \overline{\ex(M)}, the closure of the extreme points of $M$, and the relative Cantor-Bendixson rank of \overline{\ex(M)} with respect to \ex(M). We also address the optimality of these bounds.Comment: 48 page

Quasi-Isometric Embeddings of Symmetric Spaces

We prove a rigidity theorem that shows that, under many circumstances, quasi-isometric embeddings of equal rank, higher rank symmetric spaces are close to isometric embeddings. We also produce some surprising examples of quasi-isometric embeddings of higher rank symmetric spaces. In particular, we produce embeddings of $SL(n,\mathbb R)$ into $Sp(2(n-1),\mathbb R)$ when no isometric embeddings exist. A key ingredient in our proofs of rigidity results is a direct generalization of the Mostow-Morse Lemma in higher rank. Typically this lemma is replaced by the quasi-flat theorem which says that maximal quasi-flat is within bounded distance of a finite union of flats. We improve this by showing that the quasi-flat is in fact flat off of a subset of codimension $2$.Comment: Exposition improved, outlines of proofs added to introduction. Typos corrected, references added. Also some discussion of the reducible case adde

Investigating the Distribution of Password Choices

In this paper we will look at the distribution with which passwords are chosen. Zipf's Law is commonly observed in lists of chosen words. Using password lists from four different on-line sources, we will investigate if Zipf's law is a good candidate for describing the frequency with which passwords are chosen. We look at a number of standard statistics, used to measure the security of password distributions, and see if modelling the data using Zipf's Law produces good estimates of these statistics. We then look at the the similarity of the password distributions from each of our sources, using guessing as a metric. This shows that these distributions provide effective tools for cracking passwords. Finally, we will show how to shape the distribution of passwords in use, by occasionally asking users to choose a different password

The world crisis: global financial governance: principles of reform

It is now increasingly acknowledged that complex global processes, from the financial to the ecological, connect the fate of communities across the world. Yet the problem-solving capacity of the existing system of global institutions is in many areas not effective, accountable, or fast enough to resolve current global dilemmas. What has recently been called the paradox of our times refers to the fact that the collective issues we must grapple with are of growing extensity and intensity, and yet the means for addressing them are weak and incomplete.1 There are a variety of reasons for the persistence of these problems, but at the most basic level the persistence of this paradox remains an issue of governance. One significant problem in this regard is that a growing number of issues span both the domestic and the international domains. The institutional fragmentation and competition between states can lead to these global issues being addressed in an ad hoc and dissonant manner. A second problem is that even when the global dimension of a problem is acknowledged, there is no clear division of labour among the myriad of international institutions that seek to address them: their functions often overlap, their mandates conflict, and their objectives often become blurred. A third problem is that the existing system of global governance suffers from severe deficits of accountability and inclusion. This problem is especially relevant in regard to how less economically powerful states and, hence, their entire populations, are marginalised or excluded from decisionmaking. This paper describes the current global economic crisis as intimately related to a problem of governance, and articulates simple principles by which the reform of governance can be guided. Increased accountability through participatory reform, we argue, helps to underwrite effectiveness

The Rhetoric of Mass Incarceration

Professor David Coogan teaches rhetorical theory and criticism and composition, as well as service learning, for the VCU Department of English. For the last ten years, he has also taught and collaborated with writers in the Richmond City Jail, in a program called Open Minds. In his published and forthcoming work on the importance of writing for social and personal transformation – Electronic Writing Centers: Computing the Field of Composition, The Public Work of Rhetoric: Citizen Scholars and Community Engagement (co-edited with John Ackerman), Writing Our Way Out: Memoirs from Jail, and Memoirs of Mass Incarceration: The Rhetoric of Revolutionaries, Witnesses and Survivors (forthcoming in 2017) – Professor Coogan explores ways of finding oneself in the midst of extreme confusion, guilt, social injustice, and searing pain. From his work with writers in prison, he has gathered profound insights into the writing process for those who are often silenced, and has both taught with writers and learned from them as well. In this conversation, he expands on his experiences and describes the nature of this important work

Harry Potter and metaphysical hospitality

Continuing the series of investigations of hospitality practices in different locations, Kevin O'Gorman and David Brooks explore what muggles can learn from the hospitality experienced in the world of wizardry. These epic fantasies have some mind-expanding messages for those who will listen