Global small data weak solutions of 2-D semilinear wave equations with scale-invariant damping, I

Li Qianqian, Wang Dinghuai, Yin Huicheng

There is an interesting open question: for the $n$-D ($n\ge 1$) semilinear wave equation with scale-invariant damping ${\partial }_t^{2}u-\hat{I}”u+\frac{\hat{I}}{¼}t{\partial }_{t}u=|u{|}^p$, where $t\ge 1…