Séminaire Lotharingien de Combinatoire, 91B.2 (2024), 12 pp.

Colin Defant, Rachana Madhukara and Hugh Thomas

Toric and Permutoric Promotion

Abstract. We introduce toric promotion as a cyclic analogue of Schützenberger's promotion operator. Toric promotion acts on the set of labelings of a graph G; it is defined as the composition of certain toggle operators, listed in a natural cyclic order. We provide a surprisingly simple description of the orbit structure of toric promotion when G is a forest. We then consider more general permutoric promotion operators, which are defined as compositions of the same toggle operators, but in permuted orders. When G is a path graph, we provide a complete description of the orbit structures of all permutoric promotion operators, showing that they satisfy the cyclic sieving phenomenon.


Received: November 15, 2023. Accepted: February 15, 2024. Final version: April 1, 2024.

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