Quasinormable Fréchet spaces and M. W. Wong’s inequality

A short proof of M. W. Wong’s inequality \(\left\Vert J_{-s}\varphi \right\Vert _p \le \varepsilon \left\Vert J_{-t}\varphi \right\Vert _p + C \left\Vert \varphi \right\Vert _p\) ${∥J_{-s},\phi ∥}_p\le \epsilon {∥J_{-t},\phi ∥}_p+C{∥\phi ∥}_p$ is given.