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Mathematicians have found a new upper limit to the Ramsey number

quantamagazine.org

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Re: Mathematicians have found a new upper limit to the Ramsey number

#11

Post by avgcorrection »

davnicwil wrote: post #10
enriquto wrote: post #9

Earlier quoted context omitted.

It's an invasion of privacy. Imagine that a post appears under your name with a date/time where you are supposed to be working. If you are paid by somebody else, this may get you into trouble, or even fired.

In fairness in such an extreme situation it seems likely there would be a conversation where you'd have the opportunity to explain. If there weren't, well, probably you're better off?

> If there weren't, well, probably you're better off?

That’s for the person to do something with or not. :) Not something that moderators should intervene in indirectly.

Re: Mathematicians have found a new upper limit to the Ramsey number

#12

Post by carbotaniuman »

enriquto wrote: post #9
lloydatkinson wrote: post #7

Earlier quoted context omitted.

Why?

It's an invasion of privacy. Imagine that a post appears under your name with a date/time where you are supposed to be working. If you are paid by somebody else, this may get you into trouble, or even fired.

There is no privacy invasion here (that isn't even the right argument). If you think that HN misrepresents the data then sure that's a valid concern, but it's not a privacy invasion. But really, the HN date is when it got exposed initially.

Re: Mathematicians have found a new upper limit to the Ramsey number

#16

Post by itscodingtime »

davidnc wrote: post #14
itscodingtime wrote: post #13

Can someone explain to me why changing the top right and bottom right edges to blue in the R(3) = 6 does not work ?

There's still a red clique. And changing any of those 3 to blue crates a blue clique.

Ah, thanks. I see it now.

Re: Mathematicians have found a new upper limit to the Ramsey number

#17

Post by leeoniya »

lloydatkinson wrote: post #7
bmacho wrote: post #4

Earlier quoted context omitted.

Moderators often resubmit submissions with fake time. (I pretty much hate this. I don't like people lying things about me, like I was using HN at a time I wasn't. Be aware of this.)

Why?

pretty sure it's because HN's position/rank algorithm is heavily weighted towards post age. so if it got upmodded but retained yesterday's timestamp it would not get much hang time.

(speaking as someone with a few previous second-chance submissions)

Re: Mathematicians have found a new upper limit to the Ramsey number

#18

Post by tommiegannert »

scrlk wrote: post #5
georgehill wrote: post #2

I submitted this link 1 day ago, but I am not sure why it's on the front page now, as it says I posted it just 1 hour ago https://news.ycombinator.com/submitted?id=georgehill

dang explains the mechanics behind the second-chance pool here: https://news.ycombinator.com/item?id=26998308 Regarding timestamp inconsistencies: https://news.ycombinator.com/item?id=19774614

I wonder what would happen to Reddit if moderators could order posts manually (other than stickies).

Re: Mathematicians have found a new upper limit to the Ramsey number

#19

Post by [deleted] »

leeoniya wrote: post #17
lloydatkinson wrote: post #7

Earlier quoted context omitted.

Why?

pretty sure it's because HN's position/rank algorithm is heavily weighted towards post age. so if it got upmodded but retained yesterday's timestamp it would not get much hang time. (speaking as someone with a few previous second-chance submissions)

[deleted]

Re: Mathematicians have found a new upper limit to the Ramsey number

#20

Post by OJFord »

tromp wrote: post #8

> Can we improve 3.993 to 3.9? Maybe to 3.4? And what about 3?” Pi is feeling a little left out. If that turns out to be the true asymptotic behavior of Ramsey numbers, it would make one of the worst ever methods for computing digits of pi...

I thought it was entertainingly specific, and fortunately the abstract at least [0] was slightly less immediately beyond me than I feared, to satisfy my curiosity a bit:

The main proof is an improvement to the 4^k bound (standing since 1935) to (4-eps)^k for some epsilon.

They additionally prove (I guess they have properties that make it slightly easier than other rounder/bigger numbers?) it for eps=2^-10 and eps=2^-7 specifically.

(3.993 then comes from the latter, 4 minus it gives 3.9921 and change, but of course you need to round that up to 3.993 in order to say it's a bound: it's not definitely less than 3.992, since it could lie between the two.)

So yes maybe/it probably can be improved from 3.993, because that's a bit of a tangential claim anyway - the main thing is that it's 'some non-zero amount less than 4'^k.

(But mostly yes it was beyond me, I won't pretend to be able to even attempt to understand the proof really.)

[0]: https://arxiv.org/abs/2303.09521

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