Some Remarks on Strichartz Estimates for Homogeneous Wave Equation
  We give several remarks on Strichartz estimates for homogeneous wave equation with special attention to the cases of $L^\infty_x$ estimates, radial solutions and initial data from the inhomogeneous Sobolev spaces. In particular, we give the failure of the endpoint estimate $L^4_t L^\infty_x$ for $n=2$. 
Daoyuan Fang, and Chengbo Wang