Séminaire Lotharingien de Combinatoire, 80B.23 (2018), 12 pp.

Pavel Galashin, Steven N. Karp and Thomas Lam

The Totally Nonnegative Grassmannian is a Ball

Abstract. We prove that three spaces of importance in topological combinatorics are homeomorphic to closed balls: the totally nonnegative Grassmannian, the compactification of the space of electrical networks, and the cyclically symmetric amplituhedron.

Received: November 14, 2017. Accepted: February 17, 2018. Final version: April 1, 2018.

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