Spectral cluster estimates for C1,1 metrics

<abstract abstract-type="TeX"><p>In this paper, we establish <i>L<sup>p</sup></i> norm bounds for spectral clusters on compact manifolds, under the assumption that the metric is <i>C</i><sup>1,1</sup>. Precisely, we show that the <i>L<sup>p</sup></i> estimates proven by Sogge in the case of smooth metrics hold under this limited regularity assumption. It is known by examples of Smith-Sogge that such estimates fail for <i>C</i><sup>1,α</sup> metrics if α < 1.