On the second parameter of an $(m, p)$-isometry
  A bounded linear operator $T$ on a Banach space $X$ is called an $(m, p)$-isometry if it satisfies the equation \sum_{k=0}^{m}(-1)^{k} {m \choose k}\|T^{k}x\|^{p} = 0$, for all $x \in X$. In this paper we study the structure which underlies the second parameter of $(m, p)$-isometric operators. We concentrate on determining when an $(m, p)$-isometry is a $(\mu, q)$-isometry for some pair ($\mu, q)$. We also extend the definition of $(m, p)$-isometry, to include $p=\infty$ and study basic properties of these $(m, \infty)$-isometries. 
Philipp Hoffmann, Michael Mackey and M\'iche\'al \'O Searc\'oid
math.FA