The Differential Structure of an Orbifold

We prove that the underlying set of an orbifold equipped with the ring of smooth real-valued functions completely determines the orbifold atlas. Consequently, we obtain an essentially injective functor from orbifolds to differential spaces.Comment: V3: Final version. Removed a superfluous "2" from some example

'He's dead but he won't lie down!' Posthumous characterisation: the symbiosis of ghost and man, of spirit and flesh

In the case of some Shakespearian characters (e.g.Richard II and Julius Caesar) their postmortal presence influences our reading of their characters when they were alive. The past being is morally nourished by his postmortality. Of course, Shakespeare himself is magnified by his postmortal reputation

From Yeezus to Pablo: An Existential Theology between God, Blackness, and Being

Kanye West has transformed and transfigured from a young rapper representing the Southside of Chicago, to an icon, a rap genius, a god. His persona has continually evolved from his arrival on the Hip Hop scene, leading to his emergence as, Yeezus. This essay argues for an investigation of Kanye’s theological claims through the lens of his own body, particularly the balance between how he conveys what it is like to be a black man in an American culture plagued by racism and the potential of the black body to assert its incarnate godlikeness in his music. In addition, this essay explores West’s newest record, The Life of Pablo, and its implications for Yeezus. The results of the study highlight Kanye’s evolution—somewhere between Yeezus, black god, new slave, and now, Pablo (Paul). I argue that Yeezus represents a deification and The Life of Pablo is a de-deification, as communicated in the words of Kanye himself

Noncommutative String Theory, the R-Matrix, and Hopf Algebras

Motivated by the form of the noncommutative *-product in a system of open strings and Dp-branes with constant nonzero Neveu-Schwarz 2-form, we define a deformed multiplication operation on a quasitriangular Hopf algebra in terms of its R-matrix, and comment on some of its properties. We show that the noncommutative string theory *-product is a particular example of this multiplication, and comment on other possible Hopf algebraic properties which may underlie the theory.Comment: 14 pages using LaTeX, uses amssymb.st

Thermonuclear burst oscillations

Burst oscillations, a phenomenon observed in a significant fraction of Type I (thermonuclear) X-ray bursts, involve the development of highly asymmetric brightness patches in the burning surface layers of accreting neutron stars. Intrinsically interesting as nuclear phenomena, they are also important as probes of dense matter physics and the strong gravity, high magnetic field environment of the neutron star surface. Burst oscillation frequency is also used to measure stellar spin, and doubles the sample of rapidly rotating (above 10 Hz) accreting neutron stars with known spins. Although the mechanism remains mysterious, burst oscillation models must take into account thermonuclear flame spread, nuclear processes, rapid rotation, and the dynamical role of the magnetic field. This review provides a comprehensive summary of the observational properties of burst oscillations, an assessment of the status of the theoretical models that are being developed to explain them, and an overview of how they can be used to constrain neutron star properties such as spin, mass and radius.Comment: Preprint of article submitted to Annual Reviews of Astronomy and Astrophysics (2012). 35 page