Hacker Newsnew | past | comments | ask | show | jobs | submitlogin

So these are all powers of 2 minus 2, and it looks like from the article that the pattern doesn’t exist in 2^8 - 2 or higher. Is there any description a layperson might understand as to why it stops instead of going on forever!


The proof that it stops instead of going on forever is here: https://arxiv.org/abs/0908.3724

It’s more than 200 pages of pretty technical mathematics, so I’m reasonably confident that there is no description a layperson might understand.


They’re all double the last dimension plus two, without skipping any in that sequence - but that offers no insight into why it wouldn’t hold for 254.


> They’re all double the last dimension plus two, without skipping any in that sequence - but that offers no insight into why it wouldn’t hold for 254.

Wikipedia at least gives a literature reference and concise explanation for the reason:

> https://en.wikipedia.org/w/index.php?title=Kervaire_invarian...

"Hill, Hopkins & Ravenel (2016) showed that the Kervaire invariant is zero for n-dimensional framed manifolds for n = 2^k− 2 with k ≥ 8. They constructed a cohomology theory Ω with the following properties from which their result follows immediately:

* The coefficient groups Ω^n(point) have period 2^8 = 256 in n

* The coefficient groups Ω^n(point) have a "gap": they vanish for n = -1, -2, and -3

* The coefficient groups Ω^n(point) can detect non-vanishing Kervaire invariants: more precisely if the Kervaire invariant for manifolds of dimension n is nonzero then it has a nonzero image in Ω^{−n}(point)"

Paper:

Hill, Michael A.; Hopkins, Michael J.; Ravenel, Douglas C. (2016). "On the nonexistence of elements of Kervaire invariant one"

* https://arxiv.org/abs/0908.3724

* https://annals.math.princeton.edu/2016/184-1/p01


Here is my guess. Number of dimensions is more like a hyperparameter than a parameter. Each time you increase the dimension by 1 you get a new world. You cane expect a simple pattern to go on forever.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: