Leclerc's conjecture on a cluster structure for type A Richardson varieties

TL;DR

This paper proves that Leclerc's conjectural cluster structure on type A Richardson varieties is indeed a valid cluster structure by comparing it with Ingermanson's combinatorial approach and showing their equivalence.

Contribution

It demonstrates that Leclerc's conjecture holds in type A by establishing the equivalence of two different cluster structures for Richardson varieties.

Findings

Leclerc's conjectural cluster structure is confirmed in type A.

The quivers of the two cluster structures coincide.

Clusters are related by the twist map for Richardson varieties.

Abstract

Leclerc constructed a conjectural cluster structure on Richardson varieties in simply laced types using cluster categories. We show that in type A, his conjectural cluster structure is in fact a cluster structure. We do this by comparing Leclerc's construction with another cluster structure on type A Richardson varieties due to Ingermanson. Ingermanson's construction uses the combinatorics of wiring diagrams and the Deodhar stratification. Though the two cluster structures are defined very differently, we show that the quivers coincide and clusters are related by the twist map for Richardson varieties, recently defined by Galashin--Lam.