: In 1921, Landau wrote a letter to Hardy including a proof of the inequality \begin{align*} \sum_{n=0}^{\infty}|\phi(n)-\phi(n+1)|^{p}\geq \left(\frac{p-1}{p}\right)^{p}\sum_{n=1}^{\infty}\frac{|\phi(n)|^{p}}{n^{p}} \end{align*} which holds for all finitely supported $\phi:\N_0\to\R$ such that $\phi(0)=0$ (here $1<p<\infty$ is a fixed number). This inequality was stated before … Continue reading Colloquium: Tuesday, November 22, 2 pm. Speaker: Yehuda Pinchover (Technion). Title: “Some aspects of Hardy-type inequalities”.