Matroidal mixed Eulerian numbers
Algebraic Combinatorics, Volume 7 (2024) no. 5, pp. 1479-1506.

We make a systematic study of matroidal mixed Eulerian numbers which are certain intersection numbers in the matroid Chow ring generalizing the mixed Eulerian numbers introduced by Postnikov. These numbers are shown to be valuative and obey a log-concavity relation. We establish recursion formulas and use them to relate matroidal mixed Eulerian numbers to the characteristic and Tutte polynomials, reproving results of Huh–Katz and Berget–Spink–Tseng. Generalizing Postnikov, we show that these numbers are equal to certain weighted counts of binary trees. Lastly, we study these numbers for perfect matroid designs, proving that they generalize the remixed Eulerian numbers of Nadeau–Tewari.

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DOI: 10.5802/alco.382
Classification: 05B35, 05A15, 05E99
Keywords: Eulerian numbers, Chow rings of matroids, log concavity, Tutte polynomials

Katz, Eric 1; Kutler, Max 1

1 The Ohio State University Department of Mathematics 231 West 18th Avenue Columbus OH 43210-1174
License: CC-BY 4.0
Copyrights: The authors retain unrestricted copyrights and publishing rights
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Katz, Eric; Kutler, Max. Matroidal mixed Eulerian numbers. Algebraic Combinatorics, Volume 7 (2024) no. 5, pp. 1479-1506. doi : 10.5802/alco.382. https://alco.centre-mersenne.org/articles/10.5802/alco.382/

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