“…Based on this, he showed that every isometry of the Teichmüller space T (S g,0 ) with the Teichmüller metric is an element of the extended mapping class group MCG ± (S g,0 ), and that every local isometry is the restriction of a global isometry. Since then the isometry rigidity problem of the Teichmüller metric has been extensively studied (see [Roy71], [EK74a], [EK74b], [EG96], [Lak97], [AP98], [Iva01], [Mar03], [EM03], [FW10], [MM13]). This result was extended by Erale-Kra in [EK74a] to the case of Riemann surfaces with n > 0, and in [EK74b] to the case of isometries between Teichmüller spaces.…”