Rigidity of the ${\mathrm{Sine}}_{\beta }$ process

We show that the ${\mathrm{Sine}}_{\beta }$ point process, defined as the scaling limit of the Circular Beta Ensemble when the dimension goes to infinity, and generalizing the determinantal sine-kernel process, is rigid in the sense of Ghosh and Peres: the number of points in a given bounded Borel set $B$ is almost surely equal to a measurable function of the position of the points outside $B$.