Conformal Dimension of the Brownian Graph

TL;DR

This paper proves that the graph of one-dimensional Brownian motion is almost surely minimal for conformal dimension and introduces new examples of such minimal sets, expanding understanding of conformal geometry.

Contribution

It establishes the minimality of Brownian motion graphs for conformal dimension and introduces Bedford-McMullen type sets as new examples of minimal sets.

Findings

Brownian graph is almost surely minimal for conformal dimension

Bedford-McMullen self-affine sets with uniform fibers are minimal

Construction of rich families of minimal sets using Fuglede's modulus

Abstract

Conformal dimension of a metric space $X$, denoted by $\dim_C X$, is the infimum of the Hausdorff dimension among all its quasisymmetric images. If conformal dimension of $X$ is equal to its Hausdorff dimension, $X$ is said to be minimal for conformal dimension. In this paper we show that the graph of the one dimensional Brownian motion is almost surely minimal for conformal dimension. We also give many other examples of minimal sets for conformal dimension, which we call Bedford-McMullen type sets. In particular we show that Bedford-McMullen self-affine sets with uniform fibers are minimal for conformal dimension. The main technique in the proofs is the construction of ``rich families of minimal sets of conformal dimension one''. The latter concept is quantified using Fuglede's modulus of measures.