Liu, Meng Yun et Wang, Cheng Bo, Global Existence for Some 4-D Quasilinear Wave Equations with Low Regularity, Acta mathematica Sinica. English series (Print) , 34(4), 2018, pp. 629-640
In this paper, we prove the global existence for some 4-D quasilinear wave equations with small, radial data in H3 . H2. The main idea is to exploit local energy estimates with variable coefficients, together with the trace estimates.