|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|4655014||1632926||2017||15 صفحه PDF||سفارش دهید||دانلود رایگان|
The Ish arrangement was introduced by Armstrong to give a new interpretation of the q,tq,t-Catalan numbers of Garsia and Haiman. Armstrong and Rhoades showed that there are some striking similarities between the Shi arrangement and the Ish arrangement and posed some problems. One of them is whether the Ish arrangement is a free arrangement or not. In this paper, we verify that the Ish arrangement is supersolvable and hence free. Moreover, we give a necessary and sufficient condition for the deleted Ish arrangement to be free.
Journal: Journal of Combinatorial Theory, Series A - Volume 146, February 2017, Pages 169–183