Dispersive estimates for the wave and the Klein-Gordon equations in large time inside the Friedlander domain

<p style='text-indent:20px;'>We prove global in time dispersion for the wave and Klein-Gordon equation inside Friedlander domain by taking full advantage of space-time localization caustics a precise estimate number waves that may cross at given, large time. Moreover, we uncover significant difference between low frequency, regime, where exhibits worse decay than wave, unlike flat space.</p>