On the isometry group of RCD∗(K,N)-spaces

This is a post-peer-review pre-copyedit version of an article published in Manuscripta Mathematica. The final authentical version is avaible online https://doi.org/10.1007/s00229-018-1010-7We prove that the group of isometries of a metric measure space that satisfies the Riemannian curvature condition,RCD∗(K,N),is a Lie group. We obtain an optimal upper bound on the dimension of this group, and classify the spaces where this maximal dimension is attained.L. Guijarro and J. Santos-Rodríguez were supported by research grants MTM2014-57769-3-P, and MTM2017-85934-C3-2-P (MINECO) and ICMAT Severo Ochoa Project SEV-2015-0554 (MINECO). J. Santos-Rodríguez was supported by a PhD scholarship awarded byCONACY