{ "id": "0903.2555", "version": "v1", "published": "2009-03-14T16:15:29.000Z", "updated": "2009-03-14T16:15:29.000Z", "title": "Equidistribution of (X,Y)-descents, (X,Y)-adjacent pairs, and (X,Y)-place-value pairs on permutations", "authors": [ "Emeric Deutsch", "Sergey Kitaev", "Jeffrey Remmel" ], "comment": "19 pages", "categories": [ "math.CO" ], "abstract": "An $(X,Y)$-descent in a permutation is a pair of adjacent elements such that the first element is from $X$, the second element is from $Y$, and the first element is greater than the second one. An $(X,Y)$-adjacency in a permutation is a pair of adjacent elements such that the first one is from $X$ and the second one is from $Y$. An $(X,Y)$-place-value pair in a permutation is an element $y$ in position $x$, such that $y$ is in $Y$ and $x$ is in $X$. It turns out, that for certain choices of $X$ and $Y$ some of the three statistics above become equidistributed. Moreover, it is easy to derive the distribution formula for $(X,Y)$-place-value pairs thus providing distribution for other statistics under consideration too. This generalizes some results in the literature. As a result of our considerations, we get combinatorial proofs of several remarkable identities. We also conjecture existence of a bijection between two objects in question preserving a certain statistic.", "revisions": [ { "version": "v1", "updated": "2009-03-14T16:15:29.000Z" } ], "analyses": { "subjects": [ "05A15" ], "keywords": [ "permutation", "equidistribution", "place-value pair", "adjacent elements", "first element" ], "note": { "typesetting": "TeX", "pages": 19, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2009arXiv0903.2555D" } } }