Global existence and decay estimates for quasilinear wave equations with nonuniform dissipative term

We study global existence and decay estimates for quasilinear wave equations with dissipative terms in the Sobolev space $H^L \times H^{L-1}$, where $L \geq [d/2]+3$. The linear dissipative terms depend on space variable coefficient, and these terms may vanish in some compact region. For the proof of global existence, we need estimates of higher order energies. To control derivatives of the dissipative coefficient, we introduce an argument using the rescaling. Furthermore we get the decay estimates with additional assumptions on the initial data. To obtain the decay estimates, the rescaling argument is also needed.