Shard polytopes

Abstract

For any lattice congruence of the weak order on permutations, N. Reading proved that gluing together the cones of the braid fan that belong to the same congruence class defines a complete fan, called a quotient fan, and V. Pilaud and F. Santos showed that it is the normal fan of a polytope, called a quotientope. In this paper, we provide a simpler approach to realize quotient fans based on Minkowski sums of elementary polytopes, called shard polytopes, which have remarkable combinatorial and geometric properties. In contrast to the original construction of quotientopes, this Minkowski sum approach extends to type $B$.

73 pages, 35 figures; Version 2: minor corrections for final version

References in corpus (3)

• Algebraic and combinatorial structures on pairs of twin binary trees
• Removahedral congruences versus permutree congruences
• Hopf monoids and generalized permutahedra

Cited by in corpus (6)

• Celebrating Loday's Associahedron
• Acyclic reorientation lattices and their lattice quotients
• Shuffles of deformed permutahedra, multiplihedra, constrainahedra, and biassociahedra
• Rectangulotopes
• Geometric realizations of the $s$-weak order and its lattice quotients
• Separating trees and simple congruences of the weak order