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U+237C ⍼ Right Angle with Downwards Zigzag Arrow

ionathan.ch

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Re: U+237C ⍼ Right Angle with Downwards Zigzag Arrow

#301

Post by r0uv3n »

dirkt wrote: post #295
maze-le wrote: post #199

Earlier quoted context omitted.

It's used in german mathematics education (secondary level), either to mark a contradiction in a proof or more generally to mark an erroneous statement.

But I have never seen it to mark negation of a condition, that's usually done with a slash (as in ≠ ≮ ≯ ≰ ≱ ≴ ≵ ⊄ ⊅ ⊈ ⊉ ⊊ ⊋ ∉ ∌ ∄ ∦, you get the idea). So for "not a right angle" I'd have expected a "right angle" symbol with a slash through it.

But how would you position the slash to get a somewhat easy to decipher symbol? To me, the right angle symbol seems to lend itself more to this unorthodox negation through the contradiction symbol than to negation through the normal slash.

Re: U+237C ⍼ Right Angle with Downwards Zigzag Arrow

#302

Post by mike_hearn »

rich_sasha wrote: post #15

Might we run out of Unicode code points, like we (seem to) be running out of IPv4 addresses? As another comment mentions, once you add all these snowmen, with/without snow, male female and gender-neutral, in a few skin colour options (plus neutral)... it adds up. Plus, exponential growth once you consider family of snowmen (different number/genders/races of "parents", different number/gender/races of "children" and s…

We already did! That's what happened when UTF-16 was exhausted, which was never the original plan. Just like how the IPv4 internet degraded into a mess of hacks once addresses ran short (like NAT), so too did Unicode start becoming wildly more complex.

Amongst other things, hitting the limit of 16 bits meant the introduction of:

- The concept of "planes"

- UTF-16 combining characters

- UTF-32

- The newfound desire to encode emoji using combining characters, which means many apparently simple emoji are actually hacked together out of a mini programming language (e.g. black man = man emoji + skin tone modifier). Same thing for flags, which are actually two English letters mapped into a different part of the code space and then combined e.g. the British flag is G+B.

It's one reason why emoji broke so much software. It used to be that before emoji nobody cared about characters beyond the basic multilingual plane and ignored them. Then emoji came along and broke everything that assumed a UTF-16 code point == a character.

Re: U+237C ⍼ Right Angle with Downwards Zigzag Arrow

#303

Post by yreg »

chadlavi wrote: post #100
yreg wrote: post #87

I generally (perhaps naively) think that going forward knowledge loss won't be much of an issue compared to our history. Surely the archeologists of the future won't have to wonder what some tool from our times was used for or what some symbol we currently use means… They will have Wikipedia and archive.org and whatnot! But that fantasy is not compatible with reality where we are already unable to find out what is th…

On the contrary: books might survive total societal collapse, but electronics don't.

Sure, but my prediction is that the human civilization is likely to never have a total societal collapse.

Re: U+237C ⍼ Right Angle with Downwards Zigzag Arrow

#304

Post by nybble41 »

lifthrasiir wrote: post #226
nybble41 wrote: post #212

Earlier quoted context omitted.

It seem to me that this is something best handled with tag characters, like ¤XBT + (U+E007F) = ₿ (where the letters are from the tag block, U+E00xx). This mirrors one of the two systems for rendering national flags[0], just with a different starting codepoint, and can easily accommodate all the ISO 4217 currency codes and common unofficial extensions. If a system doesn't know how to render a particular glyph it can j…

That sounds interesting, but modern currency symbols are already fast-tracked anyway---they almost always get assigned in the next version of Unicode---and more than one currency symbols for given ISO 4217 code can exist so I don't think it would work.

> modern currency symbols are already fast-tracked anyway

For national currencies, perhaps. New national currencies aren't introduced all that often, and there is a lot of pressure to support them quickly as their use is often mandatory for anyone living in that jurisdiction. For new private currencies, including crypto-currencies, we don't see quite the same eagerness—the observation that new crypto-currencies were more likely to reuse existing Unicode symbols than invent new ones was a consideration in getting the Bitcoin symbol adopted, as they didn't want to open up the floodgates to large numbers of new currency symbols. The tag-based system offers a compromise.

> and more than one currency symbols for given ISO 4217 code can exist so I don't think it would work

That is a bit of a problem, but it could be handled with the variant selector codepoints, for example ¤MOP = MOP$, ¤MOP(VS1) = 圓, and ¤MOP(VS2) = 元, if the symbols have the same meaning. To save some space the VS could replace the end codepoint. For fractional units there could be a different prefix such as ¢ for 1/100 or ₥ for 1/1000 in place of the ¤, or incorporating one of the Unicode fraction codepoints for other ratios up to ⅞ (or ⅑ or ⅒). These would be rendered verbatim in the fallback version, like ¢USD.

Re: U+237C ⍼ Right Angle with Downwards Zigzag Arrow

#305

Post by maze-le »

dirkt wrote: post #295
maze-le wrote: post #199

Earlier quoted context omitted.

It's used in german mathematics education (secondary level), either to mark a contradiction in a proof or more generally to mark an erroneous statement.

But I have never seen it to mark negation of a condition, that's usually done with a slash (as in ≠ ≮ ≯ ≰ ≱ ≴ ≵ ⊄ ⊅ ⊈ ⊉ ⊊ ⊋ ∉ ∌ ∄ ∦, you get the idea). So for "not a right angle" I'd have expected a "right angle" symbol with a slash through it.

Funny enough, I've only seen it at the Gymnasium (secondary level) and not in the University a few years later -- then indeed the usual symbols were the 'slashed' relations like you've described, or the bottom symbol: ⊥ in logic. Maybe it's an idiosyncrasy of a certain subset of math teachers.

Re: U+237C ⍼ Right Angle with Downwards Zigzag Arrow

#306

Post by froh »

HuangYuSan wrote: post #162
zeteo wrote: post #138

Earlier quoted context omitted.

> (C) the thunderbolt ↯ is commonly used for "not" or more specifically for dis-proof in this area Any examples?

I believe in German (possibly also other languages) the thunderbolt ↯ is commonly used to mean "this is a contradiction" in a mathematical proof, equivalently to in English a kind of ⋕ rotated by 45° or the symbol ※. The symbol ⟂ on the other hand means "false" and is used in particular in formal logic.

Yes and no.

Yes, we indeed used and afaict still use the thunderbolt for contradiction in my German university.

However "perpendicular" and "bottom/falsum" are two different Unicode codepoints with very similar glyphs.

https://en.m.wikipedia.org/wiki/Up_tack

Re: U+237C ⍼ Right Angle with Downwards Zigzag Arrow

#307

Post by froh »

r0uv3n wrote: post #300
froh wrote: post #141

Earlier quoted context omitted.

Perpendicular + Unicode combining solidus = ⟂ + / = ⟂̸

I think perpendicular most commonly refers to lines/vectors/planes etc., while the right angle symbol refers to angles. Also, there are often multiple symbols expressing the same thing.

Yes, a sibling comment meanwhile found the right angle symbol U+221F ∟

https://news.ycombinator.com/item?id=31015104

Re: U+237C ⍼ Right Angle with Downwards Zigzag Arrow

#308

Post by [deleted] »

maze-le wrote: post #199
esperent wrote: post #165

Earlier quoted context omitted.

> the thunderbolt ↯ is commonly used for "not" or more specifically for dis-proof in this area and I don't think it's that common. At least, I don't recall seeing it ever. Maybe it's used in non-English mathematics? Wikipedia mentions it's also used in electrolysis so maybe this new one is related to that somehow?

It's used in german mathematics education (secondary level), either to mark a contradiction in a proof or more generally to mark an erroneous statement.

[deleted]

Re: U+237C ⍼ Right Angle with Downwards Zigzag Arrow

#309

Post by MzHN »

ghostoftiber wrote: post #259
esquivalience wrote: post #252

Earlier quoted context omitted.

That first link is a redirect spiral through multiple interstitial ads. Enjoyed the rest of the comment though!

Thanks for the heads up - I've edited the post to a copy of the image I uploaded to imgur.

Ironically imgur is nowadays very, very user hostile.

You can't view an image without JavaScript. Once you enable it you get "f*ck your privacy" popups, and ads if you don't have a blocker. On mobile I can no longer view anything on imgur at all, only the top bar renders for some reason. There seems to be no way around this.

It was also recently, although after the downhill, bought by a company that specializes in buying dying social media platforms and milking them dry with questionable ethics. How questionable? Well, they got into a Darknet Diaries episode https://darknetdiaries.com/episode/93/

Re: U+237C ⍼ Right Angle with Downwards Zigzag Arrow

#310

Post by yesenadam »

kens wrote: post #218
primer42 wrote: post #74

So Unicode has all these mysterious characters... but I would bet that it's still true that many people on the planet speaking common languages can't even type their name... This post is from 2015, and I'd love to know if unicode has added better support for non-English languages since then. https://modelviewculture.com/pieces/i-can-text-you-a-pile-of... Based on https://en.wikipedia.org/wiki/Bengali_(Unicode_block)…

I read that "I Can’t Write My Name" article when it came out and it's remarkably misguided. First, there are solid linguistic reasons why Unicode handles that character the way it does. Second, the article completely misunderstands how the Unicode Consortium works. Finally, the Unicode Consortium is remarkably open to character proposals from random people. The author could have written a proposal and fixed the probl…

> I am a random person who got multiple characters added to Unicode.

Tell us that story please!

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