grandes-ecoles 2021 Q24

grandes-ecoles · France · centrale-maths2__mp Sequences and Series Proof of Inequalities Involving Series or Sequence Terms
Assume that $f \in L^1(\mathbb{R})$ and $g \in L^\infty(\mathbb{R})$. Show that $f * g$ is bounded and that $\|f*g\|_\infty \leqslant \|f\|_1 \|g\|_\infty$.
Assume that $f \in L^1(\mathbb{R})$ and $g \in L^\infty(\mathbb{R})$. Show that $f * g$ is bounded and that $\|f*g\|_\infty \leqslant \|f\|_1 \|g\|_\infty$.