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Jul 20, 2021 at 11:30 comment added ABIM @AryehKontorovich Thanks, actually I just did hehe: mathoverflow.net/questions/397935/…
Jul 20, 2021 at 11:24 comment added Aryeh Kontorovich @james_t good question! Maybe ask it as a separate OP and I’ll think in the meantime…
Jul 20, 2021 at 11:17 comment added ABIM What about for multivariate outputs (i.e. functions to $\mathbb{R}^m$ instead of $\mathbb{R}$)?
Jun 10, 2018 at 14:19 comment added Aryeh Kontorovich It’s $(2D/\epsilon)^{ddim}$, where $D$ is the diameter. It’s a direct consequence of the definition of ddim. Start with $\epsilon =D/2$ and repeatedly apply the doubling property.
Jun 10, 2018 at 8:24 comment added gradstudent @AryehKontorovich Your proof uses this intermediate result about $\epsilon-$covering number of metric spaces being upperbounded by $\left ( \frac{2}{\epsilon} \right )^{ddim}$. Is there a simple proof of this?
Jun 3, 2018 at 17:32 vote accept gradstudent
Jun 2, 2018 at 13:57 comment added Pietro Majer Also, in any case finitely many balls can't cover an unbounded set, e.g. the constant maps
Jun 1, 2018 at 7:46 comment added Aryeh Kontorovich Regarding your first question on the bounded range: yes, it's necessary, even for Lipschitz functions $f:[0,1]\to [a,b]$. You can always rescale either the Lipschitz constant $L$ or the range $b-a$ to be 1, but if either is unbounded, the covering numbers will be infinite.
Jun 1, 2018 at 7:45 comment added Aryeh Kontorovich Oops, you're right! I edited the answer, and linked to a paper where the proof appears.
Jun 1, 2018 at 7:44 history edited Aryeh Kontorovich CC BY-SA 4.0
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Jun 1, 2018 at 2:38 comment added gradstudent I think I am missing something. This Lemma 4.2 or its intermediate Lemma 2.1 dont seem to have been proven in your paper. I dont see the proofs anywhere!
May 31, 2018 at 18:40 comment added gradstudent Thanks for the clarifications! So is it provably necessary that the domain and the range be bounded for such a count to be possible? Or is this need a weakness of our current methods?
May 31, 2018 at 13:56 history answered Aryeh Kontorovich CC BY-SA 4.0