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Jun 5, 2020 at 19:48 comment added Nik Weaver But it's easy enough to come up with an $h$ such that the norms tend to $1$ as $a \to 0$.
Jun 5, 2020 at 19:48 comment added Nik Weaver No, not possible. Whatever $a$ is, you can find a positive measure ball which is small enough that it is disjoint from its translation by $a$. So if you translate it by $na$ for all $n \in \mathbb{Z}$ you get an infinite sequence of disjoint sets and finiteness of $\nu$ implies that they can't all have the same measure.
Jun 5, 2020 at 17:04 comment added ABIM I've been thinking about it but is even possible to have a probability measure $\nu$ and some $a \in \mathbb{R}^n-\{0\}$ for which $\sqrt{\frac{\|h_a\|}{\|h\|}_{\infty}}$ achieves value $1$? I think it's not possible..
Jun 5, 2020 at 14:22 comment added Nik Weaver By $\alpha$ do you mean $a$? Then yes, 1 is always a lower bound.
Jun 5, 2020 at 14:18 comment added ABIM As a lower bound (when $\alpha \neq 0$) was always have 1, since the translation operator is hypercyclic no?
Jun 5, 2020 at 13:58 vote accept ABIM
Jun 5, 2020 at 13:56 vote accept ABIM
Jun 5, 2020 at 13:56
Jun 5, 2020 at 13:47 history answered Nik Weaver CC BY-SA 4.0