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chisquared

36 karma · joined November 16, 2020

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chisquared··on Fish 4.0: The Fish of Theseus
> We don't recommend oh-my-fish for various reasons

Care to elaborate a bit on those? Or is it the kind of thing that's impolite to discuss?

chisquared··on A visual proof that a^2 – b^2 = (a + b)(a – b)
There’s no need for this extension: https://news.ycombinator.com/item?id=42425681
chisquared··on A visual proof that a^2 – b^2 = (a + b)(a – b)
If b is negative, define c = -b, and use the linked result to show that

a^2 - b^2 = a^2 - (-c)^2 = a^2 - c^2 = (a + c)(a - c) = (a + b)(a - b)

chisquared··on A visual proof that a^2 – b^2 = (a + b)(a – b)
> Then you've just skipped the case when a^2 - b^2 is negative.

Not really. If b > a, then swap them to conclude that b^2 - a^2 = (b + a)(b - a), which is what the visual proof demonstrates.

Your conclusion is equivalent to saying that a^2 - b^2 = (a + b)(a - b).

chisquared··on The walls of Apple's garden are tumbling down
Steve Jobs would have agreed with you at one point.

I'm not sure what changed his mind (or if he ever even really did), but he also thought that aside from the native apps that came with the iPhone, everything else should just be a web app.

chisquared··on My First Impressions of Nix
Huh, is this what Nix users mean by “impure”?

If so, then it makes so much more sense to me now.

chisquared··on GitHub Packages Is Down
> Anyone could just change username/organization and break thousands/millions of build.

GitHub redirects you to the new name in the event of a rename and you look up the old one.

chisquared··on TabFS – a browser extension that mounts the browser tabs as a filesystem
> even package managers like pip

This reminds me of a blog post [1] I read before. Pertinent quote:

> Unbeknownst to me, even with --dry-run pip will execute arbitrary code found in the package's setup.py. In fact, merely asking pip to download a package can execute arbitrary code (see pip issues 7325 [2] and 1884 [3] for more details)!

Also seen on Twitter [4].

[1] https://moyix.blogspot.com/2022/09/someones-been-messing-wit...

[2] https://github.com/pypa/pip/issues/7325

[3] https://github.com/pypa/pip/issues/1884

[4] https://twitter.com/moyix/status/1566561433898426368

chisquared··on Problem solving with dimensional analysis
I was going to say that the title reminded me of these notes I skimmed through ages ago called “Street-fighting mathematics” [1].

Sure enough, the end of the article indicates [1] as the reference.

[1] https://ocw.mit.edu/courses/18-098-street-fighting-mathemati...

chisquared··on In the past, I've had students call my problem sets “emotionally trying”
Interesting problems!

It’s not hard to intuit the truth values of the conjectures in the first two questions. I don’t have proofs, though.

No idea about the third one.

chisquared··on Ask HN: Math books you recommend just for the way they are written?
David Williams’ Probability with Martingales is a personal favourite. And I’m not the only one.
chisquared··on Exec who cleaned up Enron calls FTX mess 'unprecedented'
Almost everything here is an unmitigated disaster. However,

> the secret exemption of Alameda from certain aspects of FTX.com’s auto-liquidation protocol

— barring the part where this is secret — this seems like it would make some sense?

Alameda was, by my understanding, meant to be a market maker for the markets that FTX allowed its customers to trade in. You probably don’t want to apply the same auto-liquidation protocol to the market maker as you would regular traders.

Of course, I’m not a finance person, so I’d be happy to be enlightened here.

chisquared··on Podman Desktop: A Free OSS Alternative to Docker Desktop
Same. My requirements are very basic, so the switch to colima was basically seamless. I also appreciated being able to avoid Docker Desktop constantly trying to update itself (which is what ultimately motivated me to make the switch).

As a bonus, you can install the Docker CLI (e.g. `brew install --formula docker`) and use that to interact with any containers you start with colima.

chisquared··on Algebra, Topology, Differential Calculus, and Optimization Theory [pdf]
> just banging out definitions and theorems

This is pretty standard for graduate-level math texts, though. That might say something about their intended audience.

chisquared··on Algebra, Topology, Differential Calculus, and Optimization Theory [pdf]
Judging from the TOC, everything in Part I of Boyd and Vandenberghe appears in some form in the monograph, so I don't think that's it.
chisquared··on How to hide your IP address
I'm really impressed at how this article uses exactly the right amount of detail to illustrate the points it's trying to make. I've read too many that either have too much or (more typically) too little. That's a really difficult balance to achieve.
chisquared··on How to move a running process into a tmux session (2020)
I think you can just do `tmux new -A`. IIRC this is equivalent to `tmux attach || tmux`.
chisquared··on Clojure and Doom Emacs on a brand new M1 computer
Prefixing `arch -arm64` is pretty solid advice still, I think. It's really easy to inadvertently run your terminal in Rosetta, and not notice that you're running a non-native version of `brew`.
chisquared··on Ask HN: What’s a good laptop for software development at around $2k?
Note that the argument you've called ridiculous is a response to someone who does not want a

> closed source, walled garden product from a company with business practices I don't like

Such a person probably won't be using Xcode, nor has any plans of publishing to the App Store, so Xcode being closed-source isn't a factor at all here.

chisquared··on The worldly turn: A return to economics that studies the real world
The claims I made are not solely about China: they're true about very many other developing countries as well. See, for example, India.

That said, I would dispute the claim that China's economic system is distinctly non-neoliberal. In fact, most of the key elements of China's economic reform were about bringing it closer to neoliberalism rather than taking it further away.

chisquared··on The worldly turn: A return to economics that studies the real world
> How's that going in 2022?

It's brought hundreds of millions of people out of poverty [0], drastically increased their life expectancies [1], and significantly improved their chances of making it to adulthood [2].

For more, see https://www.gapminder.org.

[0] https://www.gapminder.org/tools/#$model$markers$line$encodin...

[1] https://www.gapminder.org/tools/#$model$markers$line$encodin...

[2] https://www.gapminder.org/tools/#$model$markers$line$encodin...

chisquared··on Chaining, or why you should stop returning void (2012)
I encountered code like this in a C99 project recently. I still don't understand it, but I believe it's supposed to be possible.
chisquared··on Building stuff from source
Usually you can disable this by passing `--disable-silent-rules` to `configure` and/or `V=1` to `make`.
chisquared··on Building stuff from source
`export MAKEFLAGS="-j$(nproc)"` (or `sysctl -a hw.ncpu` for Mac users).

That way you neither need to install Ninja nor remember to pass `-j` to `make`.

chisquared··on Ask HN: Best Alternative to Homebrew in 2021?
`HOMEBREW_NO_INSTALL_CLEANUP` used to be the default. Many users complained about how much space Homebrew used, and were shocked by how much they saved by doing `brew cleanup`, so now it’s done by default.
chisquared··on Arrow and the Impossibility Theorem (2012) [pdf]
I think you’re misinterpreting Arrow there. Even a voting method that requires cardinal information entails that voters be able to say which one they prefer between two candidates.

As for how a ballot capturing cardinal methods be reduced to ordinal ones: it depends on the ballot. Can you give an example of a cardinal ballot that does not induce an order or otherwise implies something about a voter’s preferences (assuming they were voting sincerely)?

chisquared··on Ask HN: Best Alternative to Homebrew in 2021?
You might be interested in `HOMEBREW_NO_INSTALL_CLEANUP` and `HOMEBREW_NO_CLEANUP_FORMULAE`. See `man brew` for details.
chisquared··on Arrow and the Impossibility Theorem (2012) [pdf]
I’m not sure what you mean by “avoiding constraints”, but Arrow’s theorem very much applies to cardinal methods too. Typically these methods (e.g. the Borda count) do not satisfy IIA.

Cardinal methods induce an order, and once a method creates an order, anything said about ordinal methods applies.

chisquared··on Show HN: Relativity: A Modern Primer
I quite like this lecture series, and I normally hate learning from YouTube videos: https://www.youtube.com/playlist?list=PLFeEvEPtX_0S6vxxiiNPr...
chisquared··on Ncdu 2: Less hungry and more Ziggy
Why is py-cryptography not comparable?

Had py-cryptography done the same thing (i.e. made the same announcement and promises, and followed through on them), I'd think we could say the exact same thing about py-cryptography as above too.

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