论文标题
特殊的愿望和预测
Special idempotents and projections
论文作者
论文摘要
我们定义有限分级Poset的任何特殊匹配，即能，回归和订单保留功能。我们认为这种功能产生的单体。该单体的同性基础称为特殊的基础。它们是间隔缩回。他们中的一些人认识了一种抛物线地图，被称为特殊预测。我们证明，在Eulerian posets中，特殊投影的图像及其补体是分级引起的子镜头。在有限的Coxeter组中，左右抛物线抛物线商的所有预测都是特殊的预测，并且对双人的一些预测也是对双人的预测。我们将结果扩展到特殊的部分匹配。
We define, for any special matching of a finite graded poset, an idempotent, regressive and order preserving function. We consider the monoid generated by such functions. The idempotents of this monoid are called special idempotents. They are interval retracts. Some of them realize a kind of parabolic map and are called special projections. We prove that, in Eulerian posets, the image of a special projection, and its complement, are graded induced subposets. In a finite Coxeter group, all projections on right and left parabolic quotients are special projections, and some projections on double quotients too. We extend our results to special partial matchings.
