Hacker News: dperrin

New comment by dperrin in "Adding an imaginary unit to a finite field"

dperrin — Mon, 17 Nov 2025 00:16:53 +0000

Spitballing here, but I suspect it's a density thing. If you are considering all prime powers up to some bound N, then the density of prime powers (edit: of size p^n with n > 1) approaches 0 as N tends to infinity. So rather than things being 1/4 like our intuition says, it should unintuitively be 1/2. I haven't given this much thought, but I suspect this based on checking some examples in Sage.

New comment by dperrin in "Do not download the app, use the website"

dperrin — Sun, 27 Jul 2025 11:46:56 +0000

I've never considered something like this before. I like the way you've phrased this too. I'm going to give this a shot for a few weeks.

New comment by dperrin in "Sleeping beauty Bitcoin wallets wake up after 14 years to the tune of $2B"

dperrin — Sat, 05 Jul 2025 09:51:26 +0000

Just speculating here, but isn't it quite possible someone wasn't intentionally sitting on it for 14 years and instead just couldn't access it? For example, if they've been sitting in prison this whole time. Something like that seems (statistically anyway) more plausible to me than getting lucky on guessing a key.

New comment by dperrin in "I don't think I can trust Google as my search engine anymore"

dperrin — Sat, 29 Mar 2025 21:06:23 +0000

They recently gave out some 3-month free trial vouchers for users to give to friends. I have a spare one that I’d be happy to share with you if you’d like. Though I don’t know the best way to get it to you since I don’t think HN has DM functionality. Username is dperrin.01 on Signal if you’d like it.

New comment by dperrin in "Show HN: I made a app that uses NFC as a physical switch to block distractions"

dperrin — Wed, 22 Jan 2025 07:55:10 +0000

Cool idea! Any chance you’ll make it available in New Zealand? I’d love to try this out.

New comment by dperrin in "Bike Manufacturers Are Making Bikes Less Repairable"

dperrin — Tue, 15 Oct 2024 00:49:43 +0000

In the thermal runaway video, you have steel bars holding the battery down. Is there risk of the battery casing blowing apart without that steel holding it down?

New comment by dperrin in "Apple Shares Full iPhone 16 and iPhone 16 Pro Repair Manuals"

dperrin — Sat, 21 Sep 2024 05:34:04 +0000

> Do you expect your iPhone 16 battery press tool to still be useful in 2 phone generations ? How many times do you see yourself replacing the iPhone 16's battery ?

Lots of my bike tools I have will take over a decade to get my money back on my stuff alone. But I get to do something I mostly enjoy. I can also help out friends/acquaintances when they need it. The same goes for this.

New comment by dperrin in "Kagi Assistant"

dperrin — Thu, 05 Sep 2024 06:49:46 +0000

Sorry to hear your experience hasn’t been great. I’ve been using it from NZ for the last six months and haven’t noticed any speed differences. Just did trips to Canada and the US recently and I didn’t notice any difference in performance.

New comment by dperrin in "Is the $139 Amazon Prime Subscription Still Worth It?"

dperrin — Sun, 04 Feb 2024 06:21:12 +0000

Are you a student? Price is showing as 99 CAD/yr otherwise.

New comment by dperrin in "FDA says 561 deaths tied to recalled Philips sleep apnea machines"

dperrin — Fri, 02 Feb 2024 10:13:30 +0000

Not sure on the accuracy or if it applies to you, but prior to getting the septoplasty my ENT did mention it might not make a big difference if overweight or obese and so often doesn’t recommend it in those cases.

For comparison, I used some of those nasal strips before surgery and the post-surgery were very comparable, so that might be an inexpensive option to try? I also recall someone mentioning some sort of nose plug thing from Amazon you could get that does the same thing.

New comment by dperrin in "FDA says 561 deaths tied to recalled Philips sleep apnea machines"

dperrin — Fri, 02 Feb 2024 05:51:23 +0000

With the exception of losing weight (already a 22 BMI) I tried pretty all of this to no avail. Turns out I had a deviated septum and surgery fixed the problem. As a bonus, I can easily breathe through my nose now.

New comment by dperrin in "A gentle introduction to two's complement"

dperrin — Thu, 23 Nov 2023 06:47:38 +0000

When I first learned two's complement I sort of accepted it as something to memorise for a test and didn't really understand (or care) why it worked.

What really made it click for me was thinking of it as modular arithmetic. If you consider 8-bit integers, they range from 0-255 and you're actually working modulo 256. So you can think of 0-127 as your non-negative numbers. The numbers from 128-255 behave as negatives modulo 256 (e.g. -1 mod 256 = 255).

New comment by dperrin in "Intro to Cryptography [pdf] (2011)"

dperrin — Sun, 02 Jul 2023 02:56:13 +0000

I’m curious why you think mathematics doesn’t need to be covered here. Immediately after covering the maths background, the author jumps into elliptic curves and I can’t think of how to understand that without understanding a little bit finite fields and groups. The maths covered seems essential for almost the entire last third of the book.