We define, for any special matching of a finite graded poset, an idempotent, regressive and order preserving function. consider the monoid generated by such functions. call idempotent element this monoid. They are interval retracts. Some them realize kind parabolic map called projections. prove that, in Eulerian posets, image projection, its complement, induced subposets. In Coxeter group, all ...

A weighted orthogonal system on the half line based on the Chebyshev rational functions is introduced. Basic results on Chebyshev rational approximations of several orthogonal projections and interpolations are established. To illustrate the potential of the Chebyshev rational spectral method, a model problem is considered both theoretically and numerically: error estimates for the Chebyshev ra...

The prevalent theory of cosmological inflation, which attempts to explain the high degree of isotropy observed from the Earth’s location in the Universe, has been criticised for being ad hoc and thermodynamically unsound. A viable alternative to inflation is the combined theory of quiescent cosmology and the Weyl curvature hypothesis, in which cosmological models are studied within a mathematic...

We give an introductory account of functional determinants of elliptic operators on manifolds and Polyakov-type formulas for their infinitesimal and finite conformal variations. We relate this to extremal problems and to the Q-curvature on even-dimensional conformal manifolds. The exposition is self-contained, in the sense of giving references sufficient to allow the reader to work through all ...

The Back-Projection Algorithm is a SAR processing approach that uses time-domain convolution of the SAR data in order to perform SAR focusing. Some benefits of this approach are exact inversion, ideal motion compensation including topography information and handling of general aperture geometries. The implementation of the Back-Projection Algorithm was done focusing on the parallelization aspec...

Previous studies in monkeys disclosed a specific arrangement of corticostriatal projections. Prefrontal and premotor areas form dense projection fields surrounded by diffuse terminal areas extending outside the densely innervated region and overlapping with projections from other areas. In this study, the mode of prefrontostriatal innervation was analyzed in rats using a 3D approach. Following ...