The acyclicity of the complex of homologous curves

We show that the complex of homologous curves of a closed, oriented surface of genus g is (g-3)--acyclic.Comment: Added citations of related work of Looijenga. Added a discussion in the introduction regarding the relationship between the results of Section 5 and work of Looijenga on the complex of separating curve

Complete Derandomization of Identity Testing and Reconstruction of Read-Once Formulas

In this paper we study the identity testing problem of arithmetic read-once formulas (ROF) and some related models. A read-once formula is formula (a circuit whose underlying graph is a tree) in which the operations are {+,x} and such that every input variable labels at most one leaf. We obtain the first polynomial-time deterministic identity testing algorithm that operates in the black-box setting for read-once formulas, as well as some other related models. As an application, we obtain the first polynomial-time deterministic reconstruction algorithm for such formulas. Our results are obtained by improving and extending the analysis of the algorithm of [Shpilka-Volkovich, 2015

All lines on a smooth cubic surface in terms of three skew lines

Jordan showed that the incidence variety of a smooth cubic surface containing 27 lines has solvable Galois group over the incidence variety of a smooth cubic surface containing 3 skew lines. As noted by Harris, it follows that for any smooth cubic surface, there exist formulas for all 27 lines in terms of any 3 skew lines. In response to a question of Farb, we compute these formulas explicitly. We also discuss how these formulas relate to Schl\"afli's count of lines on real smooth cubic surfaces.Comment: 21 pages, 5 figures, 1 table. Final version for journa

Many Low Income Women In Texas Do Not Get the Effective Contraception They Want After Giving Birth

Population Research Cente

A note on the Coulomb branch of susy Yang-Mills

We compute the force between oppositely charged W bosons in the large N limit of Yang-Mills with 16 supercharges broken to SU(N) x U(1) by a finite Higgs vev. We clarify some issues regarding Wilson line computations and show that there is a regime in which the force between W bosons is independent of separation distance.Comment: 11 pages, LaTeX, v2: misprint corrected, v3: references adde

Differences in determinants: racialized obstetric care and increases in U.S. state labor induction rates

Induction of labor (IOL) rates in the United States have nearly tripled since 1990. We examine official U.S. birth records to document increases in states’ IOL rates among pregnancies to Black, Latina, and White women. We test if the increases are associated with changes in demographic characteristics and risk factors among states’ racial-ethnic childbearing populations. Among pregnancies to White women, increases in state IOL rates are strongly associated with changes in risk factors among White childbearing populations. However, the rising IOL rates among pregnancies to Black and Latina women are not due to changing factors in their own populations but are instead driven by changing factors among states’ White childbearing populations. The results suggest systemic racism may be shaping U.S. obstetric care whereby care is not “centered at the margins” but is instead responsive to characteristics in states’ White populations

Instability and Degeneracy in the BMN Correspondence

Non-degenerate perturbation theory, which was used to calculate the scale dimension of operators on the gauge theory side of the correspondence, breaks down when effects of triple trace operators are included. We interpret this as an instability of excited single-string states in the dual string theory for decay into the continuum of degenerate 3-string states. We apply time-dependent perturbation theory to calculate the decay widths from gauge theory. These widths are new gauge theory data which can be compared with future calculations in light cone string field theory.Comment: 23 pages, no figure

The general Leigh-Strassler deformation and integrability

The success of the identification of the planar dilatation operator of N=4 SYM with an integrable spin chain Hamiltonian has raised the question if this also is valid for a deformed theory. Several deformations of SYM have recently been under investigation in this context. In this work we consider the general Leigh-Strassler deformation. For the generic case the S-matrix techniques cannot be used to prove integrability. Instead we use R-matrix techniques to study integrability. Some new integrable points in the parameter space are found.Comment: 22 pages, 8 figures, reference adde