Contents 1. Introduction 1 2. Definitions and notation 2 2.1. The diagonal 2 2.2. Matching objects 2 3. The diagonal is a right Quillen functor 3 3.1. The multicosimplicial product of standard simplices 4 3.2. Quillen functors, but not Quillen equivalences 6 4.

introduction: external root resorption is a clinical problem that often cannot be detected clinically. thus, radiography plays a crucial role in its diagnosis. however, optimal radiographic quality with minimal radiation exposure {2.1 [en] verify english word/phrase choice} is an important factor in selecting the appropriate radiographic technique. the aim of this study was the comparison of ac...

We present a new matrix-valued isospectral ordinary differential equation that asymptotically block-diagonalizes n × n zero-diagonal Jacobi matrices employed as its initial condition. This o.d.e. features a right-hand side with a nested commutator of matrices, and structurally resembles the double-bracket o.d.e. studied by R.W. Brockett in 1991. We prove that its solutions converge asymptotical...

We dedicate this paper to Professor Ron Mitchell who has been an inspiration to many generations of numerical analysts. In addition his generous spirit has infused our discipline with a sense of positive endeavour. We examine whether three diierent upwind schemes for the positive definite advection diiusion problem can yield indeenite coeecient matrices. In particular, in line with the increasi...

We call a matrix triadic if it has no more than two nonzero off-diagonal elements in any column. A symmetric tridiagonal matrix is a special case. In this paper we consider LXLT factorizations of symmetric triadic matrices, where L is unit lower triangular and X is diagonal, block diagonal with 1×1 and 2×2 blocks, or the identity with L lower triangular. We prove that with diagonal pivoting, th...

background: detection of women at risk for dystocia will allow physicians to make preparations and treatment decisions that can minimize maternal and neonatal morbidity. we aimed to determine the risk factors for dystocia in nulliparous women. methods: this case series enrolled 447 nulliparous women who presented with a single pregnancy in the vertex presentation and gestational age of 38-42 we...