BB(3, 4) > Ack(14) • Hacker News Board

Re: BB(3, 4) > Ack(14)

#111

Post by jonahx » Fri, May 24, 2024, 7:40 PM UTC

addaon wrote: post #110

jonahx wrote: post #92

Earlier quoted context omitted.

Do you know of any (hand-wavy is ok) intuitive explanation for why this machine will halt, beyond the inductive proof's given in your article? Just watching the machine run, I would guess at some kind of infinite behavior. It is remarkable that this is not the case.

> Do you know of any (hand-wavy is ok) intuitive explanation for why this machine will halt, beyond the inductive proof's given in your article? If the Halting problem could be solved by intuition, it wouldn't be much of a problem.

Yet in this case there is a proof that it halts, and that proof contains an argument. I was asking for an explanation of the essence of that argument, if simplifying it is possible.

Re: BB(3, 4) > Ack(14)

#112

Post by archermarks » Fri, May 24, 2024, 10:16 PM UTC

nextaccountic wrote: post #93

jamesaross wrote: post #60

Earlier quoted context omitted.

I love these puzzles. GNU C supports a label as value for computed goto. This is useful for direct threaded dispatch. You trade off a branch instruction for an address lookup, but it makes the code more structured. int main(void) { void* A[] = {&&A0, &&A1, &&A2, &&A3}; void* B[] = {&&B0, &&B1, &&B2, &&B3}; void* C[] = {&&C0, &&C1, &&C2, &&C3}; goto *A[SCAN]; A0: WRITE(1); RIGHT; goto *B[SCAN]; A1: WRITE(3); LEFT ; go…

> GNU C supports a label as value for computed goto. Why doesn't any modern C standard like C23 include this? Seems like a glaring omission.

Sometimes, the fact that one implementation includes it can make it actually more difficult to standardize, if there are some implementation details that are disagreeable (see GNU's nested functions)

Re: BB(3, 4) > Ack(14)

#113

Post by j2kun » Sat, May 25, 2024, 3:13 AM UTC

mcherm wrote: post #21

j2kun wrote: post #14

Earlier quoted context omitted.

Finding bigger busy beaver numbers is not exactly foundational. More like recreational. If it were foundational it would be peer reviewed in a journal article, not posted on a blog.

> If it were foundational it would be peer reviewed in a journal article, not posted on a blog. What I think you are doing here is to DEFINE "foundational work" as something that gets published in a journal. I don't mind if you use that definition, but if you do then the fact that all foundational work is published in journals is not insightful or informative, it is merely the definition. If, on the other hand, you i…

In typical mathematical style, a good definition comes from the properties you observe and desire to hold true in your axiomatic system.

Re: BB(3, 4) > Ack(14)

#114

Post by yzydserd » Sat, May 25, 2024, 7:41 AM UTC

pollyturples wrote: post #26

TeMPOraL wrote: post #22

Earlier quoted context omitted.

Because Discord is a proprietary glorified IRC SaaS; its contents are, by nature, ephemeral and under control of the vendor. I'd expect such links to rot very quickly. Collaborating on Discord is fine. Important results, including citations backing them, should really be published or at least replicated in more durable medium that's less susceptible to link rot, and easier to archive. Today, that's PDFs in paper repo…

MySpace: 16 years (2003–2019) Friendster: 12 years (2002–2013) Google+: 8 years (2011–2019) Vine: 4 years (2013–2017) Orkut: 10 years (2004–2014) Path: 8 years (2010–2018) Yik Yak: 4 years (2013–2017) Meerkat: 2 years (2015–2017) Windows Live Messenger (MSN Messenger): 15 years (1999–2014) AIM (AOL Instant Messenger): 20 years (1997–2017) ICQ: Ongoing (since 1996) but significantly declined after the early 2000s Yaho…

ICQ 1996- June 26th, 2024.

It’s shuttering.