Constructing applicative functors

Applicative functors define an interface to computation that is more general, and correspondingly weaker, than that of monads. First used in parser libraries, they are now seeing a wide range of applications. This paper sets out to explore the space of non-monadic applicative functors useful in programming. We work with a generalization, lax monoidal functors, and consider several methods of constructing useful functors of this type, just as transformers are used to construct computational monads. For example, coends, familiar to functional programmers as existential types, yield a range of useful applicative functors, including left Kan extensions. Other constructions are final fixed points, a limited sum construction, and a generalization of the semi-direct product of monoids. Implementations in Haskell are included where possible

Marianist Doxology (Hughes)

Praise to the Trinity through Mar

Contested Spaces of Citizenship: Camps, Borders and Urban Encounters

As citizenship regulations have tightened across the world, protest and activist movements have also emerged to challenge the violence of border and migration control. Positioned at the intersection of citizenship studies and critical geography, this special issue explores how space is conceived, mobilised, used and, in turn, shaped by these political struggles. The authors argue that citizenship is inextricably and irreducibly spatial, and therefore entangled with the material and discursive dimensions of geographical places and scales. Drawing on a rich set of examples, the contributions of this issue trace how space is actively and strategically used within multiple processes of political subjectivation. Focusing on critical sites through which exclusionary logics materialise – such as camps, borders and the urban space, the papers investigate how marginal(ised) political subjects claim their rights in and through space in different and often ambiguous ways, including contestation and solidarity

The Supernova Relic Neutrino Background

An upper bound to the supernova relic neutrino background from all past Type II supernovae is obtained using observations of the Universal metal enrichment history. We show that an unambiguous detection of these relic neutrinos by the Super-Kamiokande detector is unlikely. We also analyze the event rate in the Sudbury Neutrino Observatory (where coincident neutrons from anti-nu_e + D --> n + n + e+ might enhance background rejection), and arrive at the same conclusion. If the relic neutrino flux should be observed to exceed our upper bound and if the observations of the metal enrichment history (for z<1) are not in considerable error, then either the Type II supernova rate does not track the metal enrichment history or some mechanism may be responsible for transforming anti-nu_{mu,tau} --> anti-nu_e.Comment: Matches version accepted for publication in Phys. Rev.