निरंजन

> In each case, the equation qb = a (where the unknown is q and b is 0) does not meet the criterion of having **one unique solution**. Thanks for the proof. I had read this explanation in a slightly different way, but yes, I still think the answer (for me) is unsatisfactory. but I think first we need to set some background for this exchange. The primary question I think should be DO mathematical numbers correlate with real world understanding of one, two, three at all? If yes, then does number zero correlate with the concept of nothingness? If the answer to any/both of these is "no", then I think we can throw away the cake. I feel most of the times mathematical numbers can be mapped to the real world understanding of numbers, but specially with zero it looks _slippery_ as you say. Mathematicians tend to explain how x/0 could destroy their existing established theory which I very well appreciate. The theoretical clarity mathematicians have is commendable, but then is the established theory buggy? Can it be bettered in order to capture some more intricate nuances?

frougon replying to निरंजन

In order to do any kind of maths, you need definitions and axioms. So, what is your definition of division? The usual definition in number contexts is: assuming a and b are “numbers” (which is already too vague for maths) a/b is “the” number such that (a/b)×b = a I put “the” in quotes because, for this to make sense, you need to ensure (by axiom or theorem) that such a “number” exists and is unique, for every “valid” (a,b) combination. How to do so depends on the particular kind of ”numbers” you are considering (integers, rationals, reals, etc.). *In other words, a/b is defined as the unique solution of equation qb = a (of unknown q), when this equation has a unique solution.* Now, with usual ”numbers”, including real and complex numbers, you can easily see why dividing by 0 (i.e., applying the definition to (a,b) pairs such that b = 0) is invalid with this definition: * if a ≠ 0, then there is no number q such that q×0 = a; * if a = 0, every number q verifies q×0 = a. In each case, the equation qb = a (where the unknown is q and b is 0) does not meet the criterion of having **one unique solution**. P.S.: sorry, no cake. :) (Or, beware that this is not maths and is slippery: you pretend that you're going to cut the cake into parts and that, after giving me zero of these parts, I'll have the full cake. No way!)

निरंजन

One mathematician managed to tell me why it is unacceptable in math. The reason, according to him, was the two orthogonal infinities (positive and negative). I was convinced that the problem is valid, but just because of that making 1/0 "unacceptable" or "invalid" was an inelegant solution according to me.

निरंजन replying to samcarter

A non mathematician here, but I have asked this question to so many math-people and always have got unsatisfactory answers. I am really interested in knowing how one should interpret n/0. When one says 1/2, it can be semantically understood as cutting one entity in two parts of equal size/measurement. What does it mean to say 1/0? Suppose I have one cake and I "divide it by two", I get two equal pieces of cake. After "dividing by zero" what will I get? What does it even mean??? I am enraging math, probably. :P

Skillmon

@निरंजन Wow, I only saw your issues on `expkv` today, no idea why I missed them for a month or two :) Feel free to share your thoughts on my remarks there, hopefully this time around I'll see your replies earlier :P

samcarter

Yearly reminder to myself: one can select different skins for ctan on https://ctan.org/user/settings (I think the gray one is the normally used one, don't use "default" as it disables scripts)

samcarter

A nice blog post about colour profiles and stuff https://balpha.de/2024/10/what-i-recently-learned-about-color/

samcarter

Some of the videos might be interesting https://fosstodon.org/@atypi@typo.social/113357945436693265

निरंजन replying to Skillmon

Thanks a lot for the explanation. Now I understood the actual referents of the _bad code_ and yeah, the `:D` makes sense too, especially because of the `\exp_not:o` example (the surprised `:o` also looks intentional now :joy:)!

Skillmon replying to निरंजन

Because you rarely want to use the primitive features of many primitives (which tend to be quite weird often for the unexperienced -- and sometimes for the experienced alike) except for low level optimised code, and hence using a standard interface that irons out those occasional weirdnesses and is readable and understandable to others turns out to be better code. For instance (this is a well known idiom, but still might baffle the beginner) the code `\unexpanded\expandafter{<stuff>}` is harder to read than `\exp_not:o` (once you know TeX and the `expl3` argument processor conventions). Why exactly does `\unexpanded\expandafter` expand the argument once? Why don't we use `\expandafter\unexpanded\expandafter` (which would work just as well, though be slower, uses more macro space and is more to type)? With other primitives things just turn out more complicated. Have you ever tried to use `\halign` directly (bad example, as there is no `expl3` equivalent, but in LaTeX there is `tabular` which wraps it)? Have you tried to use `\halign` in a `\hbox`-assignment? Try the same with `tabular` and you'll notice a minor difference (`\sbox0{\halign{#&#\cr a&b\cr c&d\cr}}` throws an error, `tabular` works fine, can you tell me why?). For those poor souls of us that venture into the primitve land there is the "solution" to use `\cs_new_eq:NN \__mymodule_<primitive>:w \tex_<primitive>:D` and then use that copy throughout the code, as that allows us to easily fix the primitive usages if there should ever be an interface added to `expl3` for that primitive featurer we needed.

निरंजन replying to Skillmon

> Also I like the fact that happy macros only show in bad code. The macros that actually made me happy were the ones I wrote (obviously). Maybe because I am yet to understand why it is _bad code_.. :P Anyways, I have finally started to enjoy LaTeX3.

Skillmon replying to निरंजन

because look up what `\tl_reverse:N` does and you'll notice that "Don't manipulate" doesn't work out. Also I like the fact that happy macros only show in bad code.

निरंजन

The deadly commands defined with `\tex_⟨name⟩:D` look so cute because of the `:D`. How is one supposed to be shooed away? Why is it not `\tex_⟨name⟩:N` (`N`: Never use) and `\seq_new:D` (`D`: Don't manipulate)? LaTeX3 would have made me smile every single time!

samcarter

https://www.atlasobscura.com/places/jet-bear > This means that Romans and bears cohabitated the island for centuries ... we already knew that from the xmas extravaganza 2022: ![roman_bear.png](/image?hash=bb40817283fdeaefe7db06ee9658f1b84c2ee90ec486592017c01ea6137e72cc)

samcarter replying to barbara beeton

I can understand the use of short form, "Mergenthaler Vocational Technical High School" is quite the name :P

barbara beeton replying to samcarter

Thank you! I spotted that, and had already set it aside to investigate. Mergenthaler emigrated to the U.S., settled in Baltimore (the city where I grew up), and the principal vocational school is named in his honor, although the name of the school has been "shortened" to Mervotech -- the Mergenthaler Vocational Technical High School. But I don't remember that typesetting is offered as a vocation to be pursued.

samcarter

@barbara The following link was shared on the Dante mailing list https://realdougwilson.com/writing/the-box-at-the-museum Would this be something for your collection of typography museums?

samcarter

Some creative names for Australian animals: https://fosstodon.org/@MatthewChat@mstdn.social/113311998424418498

samcarter replying to CarLaTeX

Another alternative for users without local installation: https://texdoc.org/index.html

CarLaTeX replying to निरंजन

Do you have TeXLive installed? You could type `texdoc package_name` on your terminal

samcarter replying to निरंजन

They might still be moving servers around. I don't know when they are finished.

samcarter

Oh, cute and clever birds: https://www.youtube.com/watch?v=KqSbDcks_uA They even got a duck to play with!

barbara beeton replying to निरंजन

I'm not the first to suggest this. There was an earlier Indian user group, and a lot of TeX activity there for a long time. Two TUG annual meetings were held in Trivandrum, in 2002 and 2011; I attended the 2011 edition and had an excellent experience. I will try to attend in 2025 (Trivandrum again), but that's still too far off to be sure.

frougon

Geeky stunt of the year (a GitHub contributor timeline, in 2012): ![cf109e81093887f5.png](/image?hash=cd4b77c0c842f8b5e0b5f6534f6d3fad62b3a1fe1aabafa9e7e8a19582555edd) This is real: https://github.com/tomhazledine?tab=overview&from=2012-12-01&to=2012-12-31 Source [here](https://mastodon.social/@tomhazledine/112557623035267824).

samcarter

The minted maintainer wasn't kidding when he said that with minted3, the first run might take longer :) ``` Latexmk: All targets (tikzlings-doc.pdf) are up-to-date 'pdflatex': time = 282.51 'pdflatex': time = 21.54 Processing time = 304.59, of which invoked processes = 304.05, other = 0.54. Elapsed clock time = 310.61. Number of rules run = 2 ```

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