ar X iv : m at h / 05 02 15 9 v 1 [ m at h . G T ] 8 F eb 2 00 5 POINT CONFIGURATIONS AND BLOW - UPS OF COXETER COMPLEXES
نویسندگان
چکیده
The minimal blow-ups of simplicial Coxeter complexes are natural generalizations of the real moduli space of Riemann spheres. They inherit a tiling by the graph-associahedra convex polytopes. We obtain configuration space models for these manifolds (of spherical and Euclidean Coxeter type) using particles on lines and circles. A (Fulton-MacPherson) compactification of these spaces is described and an operad-like structure is shown to appear. An enumeration of the building sets of these complexes is also given with an algorithm to compute the Euler characteristics.
منابع مشابه
ar X iv : m at h - ph / 0 60 80 20 v 1 7 A ug 2 00 6 DYNAMICAL COLLAPSE OF WHITE DWARFS IN HARTREE - AND HARTREE - FOCK THEORY
We study finite-time blow-up for pseudo-relativistic Hartreeand Hartree-Fock equations, which are model equations for the dynamical evolution of white dwarfs. In particular, we prove that radially symmetric initial configurations with negative energy lead to finite-time blow-up of solutions. Furthermore, we derive a mass concentration estimate for radial blow-up solutions. Both results are math...
متن کاملParticle Configurations And
There exist natural generalizations of the real moduli space of Riemann spheres based on manipulations of Coxeter complexes. These novel spaces inherit a tiling by the graph-associahedra convex polytopes. We obtain explicit configuration space models for the classical infinite families of finite and affine Weyl groups using particles on lines and circles. A Fulton-MacPherson compactification of...
متن کاملPoint Configurations and Coxeter Operads
The minimal blow-ups of simplicial Coxeter complexes are natural generalizations of the real moduli space of Riemann spheres. They inherit a tiling by the graph-associahedra convex polytopes. We obtain explicit configuration space models for the classical infinite families of finite and affine Weyl groups using particles on lines and circles. A Fulton-MacPherson compactification of these spaces...
متن کاملNonpositive curvature of blow - ups
Consider the following situation: MC is a complex manifold of complex dimension n, and DC is a union of smooth complex codimension-one submanifolds (i.e., DC is a smooth divisor). Examples of this situation include: (1) arrangements of projective hyperplanes in CP, as well as various blow-ups of such arrangements along intersections of hyperplanes, (2) nonsingular toric varieties (whereDC is th...
متن کاملEUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH CERN-SL-Note-2000-061 AP More Electron Cloud Studies for KEKB: Long-Term Evolution, Solenoid Patterns, and Fast Blow Up
We report recent electron-cloud studies for the Low Energy Ring (LER) of KEKB, continuing earlier investigations [1, 2]. Here we simulate the build up and decay time of the cloud for various solenoid and C-yoke configurations, discuss the electron density enhancement during the bunch passage [3], and estimate the instability threshold using the Ruth-Wang theory of fast blow up [4, 5]. Geneva, S...
متن کامل