The horoboundary and isometry group of Thurston's Lipschitz metric

We show that the horofunction boundary of Teichm\"uller space with Thurston's Lipschitz metric is the same as the Thurston boundary. We use this to determine the isometry group of the Lipschitz metric, apart from in some exceptional cases. We also show that the Teichm\"uller spaces of different surfaces, when endowed with this metric, are not isometric, again with some possible exceptions of low genus.Comment: 23 pages, 5 figures. There was a mistake in one of the lemmas. Fixing it required replacing Lemmas 7.5, 7.6, and 7.7. The new version is very close to the published versio

A note on the consistency operator

It is a well known empirical observation that natural axiomatic theories are pre-well-ordered by consistency strength. For any natural theory $T$, the next strongest natural theory is $T+\mathsf{Con}_T$. We formulate and prove a statement to the effect that the consistency operator is the weakest natural way to uniformly extend axiomatic theories

Data-Driven Reporting and Processing of Digital Archives with Brunnhilde

[Excerpt] Archivists are now several decades in to appraising, arranging, describing, preserving, and providing access to digital archives and have developed and adopted a number of tools to aid in specific tasks along the way. This article discusses Brunnhilde, a new tool developed to address one of the first steps in working with born-digital materials: characterizing the overall contents of directories or disks to enable smart evidence-based decision-making in the appraisal, arrangement, and description processes

MENCIUS\u27 JUN-ZI, ARISTOTLE\u27S MEGALOPSUCHOS, & MORAL DEMANDS TO HELP THE GLOBAL POOR

It is commonly believed that impartial utilitarian moral theories have significant demands that we help the global poor, and that the partial virtue ethics of Mencius and Aristotle do not. This ethical partiality found in these virtue ethicists has been criticized, and some have suggested that the partialistic virtue ethics of Mencius and Aristotle are parochial (i.e., overly narrow in their scope of concern). I believe, however, that the ethics of Mencius and Aristotle are both more cosmopolitan than many presume and also are very demanding. In this paper, I argue that the ethical requirements to help the poor and starving are very demanding for the quintessentially virtuous person in Mencius and Aristotle. The ethical demands to help even the global poor are demanding for Mencius jun-zi (君子chön-tzu / junzi) and Aristotle\u27s megalopsuchos. I argue that both the jun-zi and megalopsuchos have a wide scope of concern for the suffering of poor people. I argue that the relevant virtues of the jun-zi and megalopsuchos are also achievable for many people. The moral views of Mencius and Aristotle come with strong demands for many of us to work harder to alleviate global poverty

H-Spaces, Loop Spaces and the Space of Positive Scalar Curvature Metrics on the Sphere

For dimensions n greater than or equal to 3, we show that the space of metrics of positive scalar curvature on the n-sphere is homotopy equivalent to a subspace which takes the form of a H-space with a homotopy commutative, homotopy associative product operation. This product operation is based on the connected sum construction. We then exhibit an action of the little n-disks operad on this subspace which, using results of Boardman, Vogt and May implies that when n=3 or n is at least 5, the space of metrics of positive scalar curvature on the n-sphere is weakly homotopy equivalent to an n-fold loop space.Comment: 43 pages, 32 figures. In version 2 we added a line to the introduction acknowledging a relevant new result in the field. In version 3, we correct an error in the proof of the second main resul