On noncrossing and nonnesting partitions for classical reflection groups
Summary: The number of noncrossing partitions of \(\{1,2,\ldots,n\}\) with fixed block sizes has a simple closed form, given by Kreweras, and coincides with the corresponding number for nonnesting partitions. We show that a similar statement is true for the analogues of such partitions for root systems \(B\) and \(C\), defined recently by Reiner in the noncrossing case and Postnikov in the nonnesting case. Some of our tools come from the theory of hyperplane arrangements.
scientific article; zbMATH DE number 1208674