Hacker News: rfc3092

New comment by rfc3092 in "Swift at Apple: Migrating the TrueType hinting interpreter"

rfc3092 — Sat, 13 Jun 2026 14:02:36 +0000

How do I apply? Historically jobs.apple.com is a black hole unless you know people.

New comment by rfc3092 in "The Art of Money Getting"

rfc3092 — Sun, 24 May 2026 02:55:16 +0000

> I'm retired.

I am not. And I am really wary of retirees giving advice on skipping the grind, enjoy life and choose a warm feeling job. I don’t have a house and if next round of layoffs hits, it is a ticking clock for my family. I’ll take extra bucks please.

New comment by rfc3092 in "Why Mathematica does not simplify sinh(arccosh(x))"

rfc3092 — Sun, 15 Mar 2026 20:59:40 +0000

As for existential crisis, you probably have missed this one: https://news.ycombinator.com/item?id=46962402

It was really fun

New comment by rfc3092 in "Why Mathematica does not simplify sinh(arccosh(x))"

rfc3092 — Sun, 15 Mar 2026 20:32:04 +0000

- function extension is defining a function where it is not defined

- function extension is an extension that keeps (or gives) Adj property

- extended function is usually treated as originals if extension is good enough. Real analysis starts with defining real numbers and extending familiar functions onto them

- in this particular case we do not need C - even continuous extension on R works and agrees with x/x = 1 at 0

- holomorphic (analytic) extension makes function infinitely differentiable at every point of C

- because of the nature of discontinuity you can’t extend the simple arccosh in any reasonable way on C without introducing multivalued or path-dependent functions

- this continuity makes x/x=1 a reasonable simplification for CAS imo but not for complex functions as in the OP

- many things with point singularities in R have more structure in C, but x/x is not one of them. Even 1/x is of a different nature.

“You do not divide by zero” that forces you to carry x != 0 is more of a high-school construct than a real thing. Physicists ignore even more important stuff, and in the end their formulas work “just fine”.

New comment by rfc3092 in "Why Mathematica does not simplify sinh(arccosh(x))"

rfc3092 — Sun, 15 Mar 2026 16:32:51 +0000

This is what differentiates (pun intended) between Complex Algebra and Complex Analysis: complex functions in analysis are multivalued (or path dependent in some schools). Even a simple concept of value of F at complex point x becomes a topic of several lectures.

I’m algebraist at heart and training, but I remember beautiful many-layered surfaces of ordinary complex functions in books and on blackboards.

New comment by rfc3092 in "Why Mathematica does not simplify sinh(arccosh(x))"

rfc3092 — Sun, 15 Mar 2026 16:20:42 +0000

I believe this is correct: x/x = 1 everywhere except 0, where it has a removable singularity. So you can extend x/x holomorphically to full C.

This is completely different from the phenomenon described in the article: arccosh discontinuity can’t be dealt the same way. In fact complex analysis prefers to deal with it my making functions path-dependent (multi-valued).

New comment by rfc3092 in "Ask HN: How to be alone?"

rfc3092 — Mon, 09 Mar 2026 17:34:20 +0000

You’re not wrong. But the “advice” to find someone or “get out of relationship” is never helpful. It is “find a job” kinda one if you don’t understand why.

I hope you’ll find a different way to support your kids if they ever get in a dark and lonely place.

New comment by rfc3092 in "Ask HN: How to be alone?"

rfc3092 — Mon, 09 Mar 2026 17:28:16 +0000

I agree I am not a good role model for marital advice. That is why I am not giving any. All my advice is about self-care when your only company on vacation is, for whatever reason, a cat and PlayStation controller.

New comment by rfc3092 in "Ask HN: How to be alone?"

rfc3092 — Mon, 09 Mar 2026 16:23:51 +0000

It really surprises me how entrenched the idea of “gym” is in everyone’s mind. For me Pilates studio is a gym too. Maybe this is a “transcontinental” thing?

New comment by rfc3092 in "Ask HN: How to be alone?"

rfc3092 — Mon, 09 Mar 2026 16:14:54 +0000

Yes. Lonely people have a lot of time. It is rarely an issue. Motivation is.

OP complains about dreadful 60 hours and not about being too busy. I can relate.

New comment by rfc3092 in "Ask HN: How to be alone?"

rfc3092 — Mon, 09 Mar 2026 08:24:14 +0000

Visit every EU capital. Or every national park. Or every bookstore in 100km radius. Just some arbitrary traveling goal that will get you out of the house every month or two.

New comment by rfc3092 in "Ask HN: How to be alone?"

rfc3092 — Mon, 09 Mar 2026 07:47:28 +0000

There are many kinds of gyms and I’m sure you’d like some. But since we’re talking loneliness here I’d particularly recommend to check out (and hang for a while):

- bouldering gyms - circus - bodybuilding gyms - dancing studio - aikido/wrestling - boxing

If your idea of gym is 24Fitness, then yeah, it is very boring.

New comment by rfc3092 in "Ask HN: How to be alone?"

rfc3092 — Mon, 09 Mar 2026 07:12:47 +0000

> Are we talking about affording in time?

Mostly weather. There are very few locations where “bike every day” is a reasonable statement. Consistency is key.

New comment by rfc3092 in "Ask HN: How to be alone?"

rfc3092 — Mon, 09 Mar 2026 05:59:34 +0000

Gym is important to set a body routine and get it used to “flush” emotions out with sweat. Daily exercise when in vulnerable state is non-negotiable imo (but hard). Not everyone can afford to bike every day. Hence why I recommend gym first.

New comment by rfc3092 in "Ask HN: How to be alone?"

rfc3092 — Mon, 09 Mar 2026 05:52:59 +0000

I was single for 10 years after college. Then married for 7 (very very badly). Then single for another 10. I thought I will spend the rest of my days alone. I have two kids now.

New comment by rfc3092 in "Ask HN: How to be alone?"

rfc3092 — Mon, 09 Mar 2026 05:17:26 +0000

Being outdoors is a big differentiator for me. I find (uv) light exposure to noticeably improve my self being. Also I can’t stay productively in the gym for 3 hours, but I can easily cycle.

New comment by rfc3092 in "Ask HN: How to be alone?"

rfc3092 — Mon, 09 Mar 2026 03:40:00 +0000

To get things out of the way: yes it is hard being alone. But it is also hard to be with someone and is very hard to take care of kids and family and such. And it is waaay harder to be with wrong person. There are no easy roads in life and being single is one of the easiest.

Now I’ll focus on practical advise:

- gym every day. No excuses. If you don’t know what to do or lack motivation- get a personal trainer.

- besides gym pick an active “hobby”. Cycling, rollerblading, running, skiing, surfing etc. You need self-supporting way to spend time outdoors. Again: do seek instruction.

- learn to play music. It is very healing and rewarding. Also frustrating and hard. Guess what? Take classes. Joining (community) school is great. Getting into local band is amazing. Most importantly here: you do not need to talk to these people. Same goes for drawing studio.

- professional education. Maybe you always wanted to be CPA?

- deep and challenging activities: sailing, diving, flying, mountaineering etc

- checklist reading, movie watching

- study textbooks

- systematic traveling

- volunteer

- build things with your hands and give them away

- learn to recognize your emotional state and how it changes.

My “qualifications”: I was single for ~10+10 years.

New comment by rfc3092 in "C++ std::move doesn't move anything: A deep dive into Value Categories"

rfc3092 — Sun, 11 Jan 2026 16:01:23 +0000

performance-noexcept-move-constructor is great but it also complains about move assignment operators, which are completely different beasts and are practically impossible to make noexcept if your destructors throw.