# Metrics on diagram groups and uniform embeddings in a Hilbert space

### Goulnara N. Arzhantseva

Universität Wien, Austria### V. S. Guba

Vologda State University, Russian Federation### Mark V. Sapir

Vanderbilt University, Nashville, United States

## Abstract

We give first examples of finitely generated groups having an intermediate, with values in $(0,1)$, Hilbert space compression (which is a numerical parameter measuring the distortion required to embed a metric space into Hilbert space). These groups include certain diagram groups. In particular, we show that the Hilbert space compression of Richard Thompson's group $F$ is equal to $1/2$, the Hilbert space compression of $\mathbb{Z}\wr\mathbb{Z}$ is between $1/2$ and $3/4$, and the Hilbert space compression of $\mathbb{Z}\wr(\mathbb{Z}\wr\mathbb{Z})$ is between 0 and $1/2$. In general, we find a relationship between the growth of $H$ and the Hilbert space compression of $\mathbb{Z}\wr H$.

## Cite this article

Goulnara N. Arzhantseva, V. S. Guba, Mark V. Sapir, Metrics on diagram groups and uniform embeddings in a Hilbert space. Comment. Math. Helv. 81 (2006), no. 4, pp. 911–929

DOI 10.4171/CMH/80