  We consider the sharp Strichartz estimate for the wave equation on $\mathbb
R^{1+5}$ in the energy space, due to Bez and Rogers. We show that it can be
refined by adding a term proportional to the distance from the set of
maximisers, in the spirit of the classical sharpened Sobolev estimate of
Bianchi and Egnell.

Classical Analysis and ODEs;Analysis of PDEs