Séminaire Lotharingien de Combinatoire, 89B.89 (2023), 12 pp.

Allen Knutson and Gabe Udell

Interpolating between Classic and Bumpless Pipe Dreams

Abstract. We introduce hybrid pipe dreams, in which some rows are specified to contain classic pipe dream tiles (plus a couple new ones) and some to contain bumpless pipe dream tiles (albeit upside down). For each of the 2n possibilities of row specification, there is a sum over hybrid pipe dreams to compute each double Schubert polynomial. We give a bijection to swap the specifications on two adjacent rows, demonstrating the equivalence of the many formulae.


Received: November 15, 2022. Accepted: February 20, 2023. Final version: April 1, 2023.

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