Solution
= Solution
True. Multiplication by a <Schwartz function> is a bounded map $H^s(\mathbb R^n)\to H^s(\mathbb R^n)$ for every real $s$.
= Solution
True. Multiplication by a <Schwartz function> is a bounded map $H^s(\mathbb R^n)\to H^s(\mathbb R^n)$ for every real $s$.