The Nineteenth Byte

12:21 AM

Q: Is the number of polynomials with integer coefficients (and order > 0) countably infinite?

@cairdcoinheringaahing I think so.

If we consider the set of integer polynomials with fixed order, it has the size of N^n for fixed n, which has 1-to-1 correspondence to N.

Then we can map each polynomial to a point (x,y) on a plane, where x is the order and y is the integer value mapped by the above

Then traverse the points through the diagonals to get a 1-to-1 correspondence to N.

caird coinheringaahing

@Bubbler Yeah, I think my thinking is similar

It's possible to have a bijection N^n -> N for a given n, and any integer polynomial of order x can be represented as a list (or vector) N^x so can be mapped to N

Bubbler

Yes.

caird coinheringaahing

I do like countably/uncountably infinite stuff :P

Cause the statement still holds if you allow for both rational coefficients and powers, but not for real coefficients/powers, which makes sense, but it still weird

Bubbler

The diagonalization proof feels weirdly satisfying when it works out

caird coinheringaahing

12:34 AM

Yeah. The realisation I had about why diagonalization works when I was reading about Cantor's proofs ranks up there with my "Oh sh*t" maths moments

If this is true (which it looks like it), does that mean that if a challenge asks for input representing an integer polynomial, it may be allowed to take input as a single integer?

Bubbler

I don't think so

Given the task "swap the parity", we don't allow the input to have swapped parity, even though it is definitely a 1-to-1 correspondence

List of coefficients is reasonable, an integer which is a result of mapping through the correspondence function is not

(unless a language only accepts an integer as input, like FRACTRAN, where using a certain encoding is permitted)

caird coinheringaahing

12:53 AM

I'd argue that the "swap the parity" argument would fall under the "using the input to encode extra data" loophole, but a polynomial to integer mapping wouldn't

Neil

@cairdcoinheringaahing well, rational coefficients doesn't buy you anything. I'm not sure what rational powers achieves, if anything

caird coinheringaahing

@Neil Rational powers expands the "range" of polynomials to consider, but it doesn't really, because the cardinality of the set doesn't change

Neil

@cairdcoinheringaahing also I think prime factorisations can be mapped fairly directly to polynomial coefficients

Bubbler

@cairdcoinheringaahing It doesn't encode extra data, by definition of 1-to-1 correspondence. One encoded input value represents exactly one intended input value, and vice versa

Neil

@cairdcoinheringaahing I meant that given a polynomial with rational coefficients, you can get one with the same solutions with integer coefficients by multiplying by e.g. the product, or the lcm, of the denominators

caird coinheringaahing

12:59 AM

@Bubbler The correspondence itself is the extra data, which for the "swap parity" example matters. But I don't see how it would affect a polynomial based challenge

Bubbler

@cairdcoinheringaahing What if the challenge itself is "a one-to-one mapping from a polynomial to an integer"?

caird coinheringaahing

@Neil Yeah, I get the maths behind it, its more looking at it from a non-mathematical PoV makes it kinda weird that it works

Bubbler

Also if you argue "the correspondence itself is the extra data", it definitely applies to the correspondence between a polynomial and an integer too

caird coinheringaahing

@Bubbler For that challenge, yeah, I'd say such a correspondence wouldn't be allowed, but for example, if the challenge was "differentiate a polynomial", I don't see a problem

Bubbler

@cairdcoinheringaahing I think a bigger problem is that there are infinitely many possible 1-to-1 correspondence functions between a polynomial and an integer. No one can be sure you can't exploit any one of them to trivialize a given challenge.

caird coinheringaahing

1:08 AM

@Bubbler TBH, I wouldn't mind seeing an answer that exploited a challenge that way, because proving that it works would be (IMO) just as impressive as solving it a different way, for most challenges

But I do see the issue

Bubbler

Sure, finding it is impressive, but soon all the answers will be porting the trivialized solution, which is boring

caird coinheringaahing

Yeah, but ported answers aren't the fault of either the asker or the user who found the original method

Personally, I upvote all answers to my challenges, unless they're boring ports

I love it when I write an example implementation for a Sandbox draft and it turns out to be 4 bytes ಠ_ಠ

Bubbler

Also, with the exploit, the challenge itself becomes a chameleon challenge, which is not good

New Sandboxed Posts

1:39 AM

0

A: Sandbox for Proposed Challenges

Laplace transform of a polynomial This is a repost of this challenge, intended to revamp it for looser I/O formats and updated rules You are to write a program which takes an integer polynomial in \$t\$ as input and outputs the Laplace transform of this polynomial. Some definitions and properties...

caird coinheringaahing

2:21 AM

CMQ: Is it worth adding a bot/feed for new submissions to the LotM nomination post?

Bubbler

I have no strong opinion on that

Sisyphus

Final call for feedback on this - the other cops-and-robbers seems to have mostly died down.

HyperNeutrino

2:42 AM

@cairdcoinheringaahing do you mean create a TNB feed bot like the 6 we currently have?

caird coinheringaahing

@HyperNeutrino Yeah

HyperNeutrino

hm. i would be fine with that, we'd ask meta first but if you're just trying to get an opinion on if people would even be interested i'd support it if other people want it

caird coinheringaahing

Personally, I'm a fan of a bot for the Hello World challenge as well, but I do see the issue with having 8 bots posting into the room

@HyperNeutrino Like this?

HyperNeutrino

something like that

we would have to change the feed every single month but that's not too much work; i don't know if it'd make too much sense though

caird coinheringaahing

@HyperNeutrino Not for the nomination post

HyperNeutrino

2:46 AM

oh, you mean language nominations

caird coinheringaahing

Yeah

Given that the actual post for the specific language each month updates every time someone posts a new answer, I don't think it's necessary for that, but for nominations, it could be a good way to draw attention

HyperNeutrino

IMO all 6 of the current feeds draw attention to some actionable content for people in chat to take a look at, but Hello World and LotM don't really have that

i guess drawing attention to nominations for voting could be a thing; just depends how often LotM gets nominations and how prevalent the community wants the event to be to the site

Razetime

So I was trying this in Mathematica: ColorData["BrightBands"] How do I get a list of colors from this function?

caird coinheringaahing

@HyperNeutrino The nomination post is fairly new (Aug 30th), but from the start of September, only 4 languages have been nominated, so it's not even as busy as the Newly Bountied feed

In fact, New Loophole Proposal is probably less active than both HW and LotM

HyperNeutrino

ah. okay, i think that would be fine then

caird coinheringaahing

2:52 AM

Q: Nominations for my 400th answer? Might as well go for an interesting challenge

HyperNeutrino

i'm personally not a fan of Hello World feed because it doesn't really have any actions beyond "do you upvote this" and we can't have a feed for every challenge and every answer obviously

Bubbler

@Razetime Did you try Mathematica reference on ColorData?

There's also Mathematica SE

caird coinheringaahing

@HyperNeutrino I'll probably draw up a meta proposal for both feeds after I've recovered from my post-election hangover tomorrow

@HyperNeutrino TBH the main argument for it is "it'll draw attention to new languages"

Razetime

@Bubbler yep, tried it, but it doesnt show how to convert to words

caird coinheringaahing

Browsing old meta posts and ooh, look at one of our mod's chat history: codegolf.meta.stackexchange.com/q/16421/66833

Honestly, grounds for mod removal :P

Bubbler

2:56 AM

For the record, some languages have had a handful of answers but not a Hello World, e.g. Flurry

HyperNeutrino

@cairdcoinheringaahing ah. i'd forgotten about that, maybe one of the very few things i'm not proud of putting a diamond next to? it does seem that swearing is actually not part of TNB etiquette because it's straight up against SE policy which is why i (think i) haven't used expletives in a long time (or at least i try to rephrase); i fully agree with the punishment though and don't think it would be productive to argue about punishing everyone else because that's pointless

caird coinheringaahing

@HyperNeutrino Ah, don't worry about it :P Personally, I've got a couple of black marks worse than a chat suspension against me, so I'm not going to hold swearing against you :P

On the other hand, I still maintain that I deserve the mod position if one of you guys steps down, so clearly this is mod abuse !!11!!eleven or whatever the meme is

Razetime

@dzaima is there a way to cast to string in canvas?

Also which charcters get compressed the most?

HyperNeutrino

@cairdcoinheringaahing now you have me curious but i will refrain from digging through your history because i have no legitimate reason to :P yeah i think those are the only offenses i have; i think i had one requested suspension to block me from using SE but i actually have self control now. also that was before my account got yeeted so it doesn't show up anymore

caird coinheringaahing

3:12 AM

@HyperNeutrino I'm fairly open about it; I got myself 2 suspensions for voter fraud (yay sockpuppet accounts) and 1 for asking the mods to suspend me when I had exams and my self-control wasn't good enough to prevent myself from wasting time on SE

But that happened over 3 years ago, so IMO it isn't much of an issue now

HyperNeutrino

oh, oof i see. i do remember you mentioning on your nomination something about being suspended since you didn't understand how SE and its system worked. yeah for something 3 years ago i'd say it doesn't really matter anymore :+1:

caird coinheringaahing

> I won't lie, I've had a couple of issues in my past on this site. I've been suspended twice and, because of my poor understanding of the site early on, I have a poor question record (according to SE's metric, hence why I don't have the Curious badge or its related badges). However, that occurred over 3 years ago, and, since then, I believe I've been a valuable voice on both Main and Meta.

From my nomination post :P I actually got it wrong (been suspended thrice), but ¯\_(ツ)_/¯

HyperNeutrino

ah my memory is not failing me that badly, good to see :P yeah, i agree with the last part of that; tbh i would never have even imagined that if you weren't open about it lol

in hindsight i should've done a more thorough check of me getting flagged / punished cuz even though getting a 2x30 suspension for swearing is not a major issue IMO, i'd still like to be transparent when i can

caird coinheringaahing

Well, I see no downside with being open with your past, especially if one is running for moderator :P

Of course, I also trust most people to be open, in that if they were running as a mod, they'd willingly expose any issues they had in the past

HyperNeutrino

yeah, exactly. i mean if one intentionally hides things in their past even if minor, who knows what they may try to do or hide once they are a mod?

caird coinheringaahing

3:18 AM

Exactly

Of course there's a difference between actively hiding and simply overlooking something

HyperNeutrino

i was considering talking about my one-week requested suspension or account deletion but i ultimately decided that a) the deletion was neither my nor SE's mistake and simply a misunderstanding/miscommunication, and if retroactively removing accounts for being underage at creation time was something SE wanted, they wouldn't have restored my account, and b) requesting suspension was entirely unimportant and i ran out of characters in my nomination anyway

but i spent too much time thinking about those things that i never remembered if i had any actual infractions :/

caird coinheringaahing

@HyperNeutrino Yeah, I had the same idea about my suspensions, but generally I went "regardless of why, I should still mention them"

Of course, my plan now is to wait until one of you 4 steps down and then swoop in to claim the seat :P

HyperNeutrino

(in hindsight of course but) i probably should've just mentioned a brief thing for each like "i requested a suspension once but have better self control now, i got my account deleted by a miscommunication, and i have two 30m chat suspensions for swearing" and then just entertain any requests for elaboration in chat

caird coinheringaahing

@HyperNeutrino "how can you justify being unable to chat for a whole hour in 2018???" I couldn't possibly vote for you :P

HyperNeutrino

@cairdcoinheringaahing haha, good plan :P eventually one day one of us will and i might become too busy with university eventually; not sure because i'm pretty busy now and still have far more than enough time to moderate

caird coinheringaahing

3:27 AM

Honestly, I wrote up my nomination post the night before you posted yours, then while asleep, you sniped me :P I fully reckon that if I'd just posted it before I went to bed, I might have won the election. But ¯\_(ツ)_/¯ you guys are doing great

Bubbler

(Super) Nice-to-have: active mods

3

HyperNeutrino

possibly :P i mean i think you had a 2% diff to jo king (though just on initial vote). i was actually expecting to lose to you and jo king in some order; i was thinking maybe i would get voted 3rd but definitely wasn't anticipating 2nd, lol

caird coinheringaahing

@Bubbler Not to disparage Doorknob but +1

@HyperNeutrino Yeah ngl, I thought WW and JoKing were guaranteed and the real election would be between you and me :P

Of interest: what was the justification for deleting some of the standard loopholes?

HyperNeutrino

@cairdcoinheringaahing do you have some particular ones you're wondering about?

i believe a bunch were removed because underhanded is no more and as such loopholes relating to it are meaningless

and some aren't loopholes; it's not a loophole if you straight up don't even solve the problem lol

caird coinheringaahing

Most of the underhanded ones

The fact that you guys just went and deleted them, although they'd been around for years and had a +200 score

HyperNeutrino

3:35 AM

I see no particular reason to keep them around since they don't apply anymore and someone reading through the loopholes doesn't really need to see things that they'll never need to be concerned about

if there is a good reason to keep them or a meta agreement to then i'd be glad to restore them, but i'm not convinced even with a high score they'd be worth keeping around; they were very valuable at the time but site rules and consensuses change and with them what's important to have agreements for

caird coinheringaahing

Personally, I support keeping highly upvoted posts around, even if they're no longer relevant

I guess mainly for posterity

Bubbler

I'm OK with them deleted, but maybe an alternative could be a history lock?

caird coinheringaahing

3:59 AM

@Bubbler not sure if you can lock just an answer, rather than the entire post

HyperNeutrino

we could, but if they were undeleted i think we'd just leave them undeleted, since there's nothing intrinsically wrong with the loopholes, but rather they no longer have any applications left on the site

i don't personally agree but of course you could raise it on meta; they're not bad or negative like the memes

Razetime

4:58 AM

@dzaima why isn't this overlap working? Canvas, 9 bytes: ：２２＊；２２╋╋

caird coinheringaahing

5:39 AM

Any feedback on these five challenges?

Bubbler

I have no objections to all five of them

caird coinheringaahing

That's definitely a good thing to hear :P

Razetime

6:36 AM

@Neil Try it online! does peekmoor not work properly at corners?

Newly Featured Questions

7:24 AM

51

Q: Combination bike lock

The scenario After a long day's work slogging in the office and browsing stackexchange.com, I finally walk out the door at 16:58, already weary with the day. Because I am still only an intern, my current mode of transportation is on bicycle. I head over to my trusty Peugeot Reynolds 501, but bef...

123

7:43 AM

Hi all,

It is possible to get steps of solution and algorithm of solution differential equations in mathematica.

Bubbler

@123 Is it a question or an advertisement?

Or a spam?

123

It is definitely question @Bubbler

Bubbler

Then sorry, you won't likely get help here, as our site has very few Mathematica users

123

Why it seems to you it is spam :P, I am new in this room. I don't know what this is about. I saw mathematica question in this room that's why I asked. :D

Okay. So, It is my mistake I saw one discussion about mathematica in this room.

What about this room is?

Bubbler

8:01 AM

> General discussion for codegolf.stackexchange.com

123

8:12 AM

Thanks. Have a nice day all.

New Main Posts

8:25 AM

0

Q: Almost Illegal Strings (Cops)

Welcome to a cops and robbers version of Find an Illegal String. An illegal string is "a string of characters that cannot appear in any legal program in your programming language of choice" (from the linked post). For this challenge, we will define an almost illegal string, which is a string of c...

restricted-source cops-and-robbers

0

Q: Almost Illegal Strings (Robbers)

This is the robbers' thread for 'Almost Illegal Strings'. See the cop's thread for information on participating. A section from the post is includeded here for convenience. The Robbers' Challenge Find an uncracked answer. Write a program in the language specified that contains as a contiguous su...

restricted-source cops-and-robbers

dzaima

9:31 AM

@Razetime it is, that's just a noop (you're overlapping already equal things). try with ３３╋╋

@Razetime cast from what? ┤ to cast from number to string, and there are no multiline strings so casting a canvas object to one doesn't make much sense

@Razetime chars compress best in this order, going from worst (Z) to best (space). Note that this only affects the compression slightly and isn't an improvement per compressed char

@dzaima additionally, trailing spaces are free or something similar, don't quite remember what was the deal with them exactly

Razetime

9:48 AM

great thanks a lot

Razetime

10:36 AM

@dzaima Canvas, 24 bytes: ø；｛*×∔｝ｊo；∔╶２％？！／＊］＊ｒ｝ why isn't this getting centered?

dzaima

@Razetime seems " ＊" changes the canvas to a list of lines, for which the centering logic ignores spaces

ah, but even if you convert that back to a canvas object, it's already got its empty markers replaced with actual spaces so centering won't work for it either

i believe you could use ／ instead of centering

also ø；｛ → Ｈ

Neil

@Razetime not sure what you were expecting, but PeekMoore() returns empty strings for cells that haven't been drawn on

Razetime

10:55 AM

oh ok

dzaima

@dzaima i'm beginning to think that ＊ with a string second arg is broken - the docs don't say anything about this insertion thing, and on an array it does something completely different from a canvas object

Razetime

@dzaima great, that's convenient

@dzaima welp there's a lot of oddities

When in doubt I just browse your answers for a fix

dzaima

so Ｈ*×∔｝ｊo；∔ → Ｈ*×］oｎ

Razetime

Canvas, 30 bytes: [`Ｈ*×∔｝ｊo；∔╶２％？！／＊！＊］＊／｝╶┐╶½⟳`](https://dzaima.github.io/Canvas/?u=JXVGRjI4KiVENyV1MjIxNCV1RkY1RCV1RkY0QW8ldUZGMUIldTIyMTQldTI1NzYldUZGMTIldUZGMDUldUZGMUYldUZGMDEldUZGMEYlMjAldUZGMEEldUZGMDElMjAldUZGMEEldUZGM0QlMjAldUZGMEEldUZGMEYldUZGNUQldTI1NzYldTI1MTAldTI1NzYlQkQldTI3RjM_,i=MTAlMEEz,v=8)
This is what I came up with

dzaima

@Razetime ╶┐╶ → ⁷; i'd prefer ⇵ to ½

Razetime

11:13 AM

Canvas, 30 bytes

ok I fixed it

now it;s correct

Question: why is it so hard to copy stuff from output?

dzaima

@Razetime how so? seems to work fine for me)

Razetime

When I right click, it removes the selection

and Cmd + C on mac does nothing

dzaima

@Razetime weird. the textarea is set as readonly, but that shouldn't prevent copying unless your browser thinks so

Razetime

anything else I can change in the code?

dzaima

@Razetime with my suggestions you get to 24. currently trying to get 23 by moving " ＊" into the first loop

Razetime

11:20 AM

it says 25

dzaima

@Razetime so it does. misremembered

Razetime

another question: do you have a monospacer for this?

IT is very hard to add explanations for canvas

dzaima

@Razetime i used to just replace chars with the closest ascii versions manually

Razetime

bruhhhh

Razetime

12:22 PM

@dzaima Suggestion: Overlaps called with no parameters automatically perform it with (1,1)

dzaima

@Razetime that's what ｎ does. And since ２２abc∙d╋ works, I can't really merge the two

Razetime

oh, n does that

Razetime

12:40 PM

@dzaima another thing.. IndexOf function?

dzaima

@Razetime none

Razetime

:(

just eval js i suppose

Unrelated String

2:12 PM

@Razetime fullwidth codepoints in unicode are at a constant offset from the non-fullwidth equivalents

65264 if my past self is correct

or maybe it's 65248

but yeah point is it's a simple conversion

Razetime

3:01 PM

hmm

maybe I'll put up a pull request for that

@UnrelatedString looks like 65260

no, 65246

Try it online!

HyperNeutrino

3:50 PM

Every time I load a chat room it shows that there's 1 flag but it always goes away when I click the actual button. Anyone else getting the same problem?

Razetime

4:09 PM

I had that a week ago

cleared cookies

also rebooted

probably one of those fixed it

HyperNeutrino

oh it seems to have gone away now on its own. but thanks, i'll keep that in mind if it ever happens again