We introduce a diagrammatic monoidal category, the spin Brauer category, that plays the same role for the spin and pin groups as the Brauer category does for the orthogonal groups. In particular, there is a full functor from the spin Brauer category to the category of finite-dimensional modules for the spin and pin groups. This functor becomes essentially surjective after passing to the Karoubi envelope, and its kernel is the tensor ideal of negligible morphisms. In this way, the spin Brauer category can be thought of as an interpolating category for the spin and pin groups. We also define an affine version of the spin Brauer category, which acts on categories of modules for the pin and spin groups via translation functors.

We give examples of non-perverse parity sheaves on Schubert varieties for all primes.

We model scientific theories as Bayesian networks. Nodes carry credences and function as abstract representations of propositions within the structure. Directed links carry conditional probabilities and represent connections between those propositions. Updating is Bayesian across the network as a whole. The impact of evidence at one point within a scientific theory can have a very different impact on the network than does evidence of the same strength at a different point. A Bayesian model allows us to envisage and analyze the differential impact of evidence and credence change at different points within a single network and across different theoretical structures.

No one will deny John E. Hill's claim that he has written an"unabashedly didactic" book (p. xi). This is not social science,or political theory, or history as it is usually understood bythose disciplines. I do not mean that as a criticism, for thereis great merit in writing as a concerned citizen-scholar. Hillputs his political cards on the table. He is a self-described"moderate liberal" (p. xi) who wants universal health insur-ance, public funding of elections, more restraints on thecorporate sector, a more progressive tax system, more spend-ing on education, and community service programs. He alsowants liberals to rethink their attitude toward morality: Theyneed to be more forthright about the importance of morali-ty-social virtue-for the health of the Republic. In addition,Hill does not shy away from telling us that he does not like"individualistic excess" (p. ix), Alexander Hamilton, RonaldReagan, or the religious Right.