A problem of Stanley from the 1981 Banff Conference on Ordered Sets
نویسنده
چکیده
Let P be a naturally labelled, ranked (graded) poset of rank r and cardinality n. Let Hk be the set of linear extensions of P with k descents. An explicit bijection between Hk and Hn−1−r−k is constructed using the involution principle (0 k n−1− r). A problem of Richard P. Stanley from 1981 is thereby solved. 2004 Elsevier Inc. All rights reserved.
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