Fifty two years ago in Jerusalem

Short information about the conference in 1960 in Jerusalem is presented together with an interesting photo where we can find several famous mathematicians participated in this conference. To recognize the people on the photo and collect their date of birth and death took me over five years. It was plan to have ready this note in 2010 on fifty years after conference. Unfortunately, this was not possible. Stil there are three persons which are not recognized. Maybe this publication will help to recognize them. In May 2012 I was trying to publish this article in Mathematical Intelligencer, but they would be willing to consider a longer, substantially revised, version. Also Notices AMS does not publish articles about conferences.Comment: 3 pages, 1 phot

A short proof of some recent results related to Ces{\`a}ro function spaces

We give a short proof of the recent results that, for every $1\leq p< \infty,$ the Ces{\`a}ro function space $Ces_p(I)$ is not a dual space, has the weak Banach-Saks property and does not have the Radon-Nikodym property.Comment: 4 page

On the interpolation constant for subadditive operators in Orlicz spaces

Let $1\le p<q\le\infty$ and let $T$ be a subadditive operator acting on $L^p$ and $L^q$. We prove that $T$ is bounded on the Orlicz space $L^\phi$, where $\phi^{-1}(u)=u^{1/p}\rho(u^{1/q-1/p})$ for some concave function $\rho$ and $$\|T\|_{L^\phi\to L^\phi}\le C\max\{\|T\|_{L^p\to L^p},\|T\|_{L^q\to L^q}\}.$$ The interpolation constant $C$, in general, is less than 4 and, in many cases, we can give much better estimates for $C$. In particular, if $p=1$ and $q=\infty$, then the classical Orlicz interpolation theorem holds for subadditive operators with the interpolation constant C=1. These results generalize our results for linear operators obtained in \cite{KM01}

Interpolation of Ces{\`a}ro sequence and function spaces

The interpolation property of Ces{\`a}ro sequence and function spaces is investigated. It is shown that $Ces_p(I)$ is an interpolation space between $Ces_{p_0}(I)$ and $Ces_{p_1}(I)$ for $1 < p_0 < p_1 \leq \infty$ and $1/p = (1 - \theta)/p_0 + \theta /p_1$ with $0 < \theta < 1$, where $I = [0, \infty)$ or $[0, 1]$. The same result is true for Ces{\`a}ro sequence spaces. On the other hand, $Ces_p[0, 1]$ is not an interpolation space between $Ces_1[0, 1]$ and $Ces_{\infty}[0, 1]$.Comment: 28 page