Local scaling limits of quadrangulations rooted on geodesics

TL;DR

This paper establishes the local scaling limit of infinite quadrangulations when rerooted along geodesics, revealing the bigeodesic Brownian plane as the universal limit in these settings.

Contribution

It demonstrates that rerooting quadrangulations along geodesics and applying local scaling limits lead to the same universal limit space, the bigeodesic Brownian plane.

Findings

The local limit of the UIPQ rerooted far along a geodesic is the bigeodesic Brownian plane.

The same limit applies to the critical Boltzmann quadrangulations.

The results show a commutation property between local limit, scaling limit, and geodesic movement.

Abstract

We identify the local scaling limit of the Uniform Infinite Planar Quadrangulation (UIPQ) and of critical Boltzmann quadrangulations, when one simultaneously rescales the distances and reroot them far away from the root of a distinguished geodesic. The limiting space is the bigeodesic Brownian plane, which appears as the local limit of the Brownian sphere around an interior point of a geodesic. We also show that the $\overline{\mathrm{UIPQ}}$ introduced by Dieuleveut, which is the local limit of the $\mathrm{UIPQ}$ rerooted at a far away point of its infinite geodesic, has the same scaling limit. These results can be seen as a commutation property between local limit, scaling limit and moving forward on a geodesic in random quadrangulations. The proofs are based on spinal decompositions of random trees and coupling results.