Mathematics - 2017-06-05 (page 1 of 5)

Meow Mix

12:10 AM

Hi dami

Daminark

Hey @Zach!

And @Julius this is an interesting proposition for sure

Meow Mix

how are your studies

Daminark

Well enough, I guess. It's finals week which is unfortunate but eh

Secret

Last night dream:
Subnothing algebra: Consider a box filled with N billard balls like objects. Then the entropy of the N bilard balls (which are classical hence distinguishable) is given by $\textrm{ln}(N!)$.

These balls, however obey some kind of nonassociative interaction. Imagine grouping $k \leq N$ balls together, then these will nullify into nothing (represented by $0$ in the cutscene). The $0$ element, however is not an identity, since $0+0\neq 0$ but rather they act like a strange type of billard ball that will pile up in the box in an extensive manner.

Meow Mix

well good luck

Daminark

12:24 AM

Thanks!

Dodsy

12:38 AM

I'm good dami, thanks for asking.

Secret

Topological entropy

In mathematics, the topological entropy of a topological dynamical system is a nonnegative extended real number that is a measure of the complexity of the system. Topological entropy was first introduced in 1965 by Adler, Konheim and McAndrew. Their definition was modelled after the definition of the Kolmogorov–Sinai, or metric entropy. Later, Dinaburg and Rufus Bowen gave a different, weaker definition reminiscent of the Hausdorff dimension. The second definition clarified the meaning of the topological entropy: for a system given by an iterated function, the topological entropy represents the...

Turns out it does exists

Dodsy

@Secret That's a trippy dream.

Secret

yeah, I am not really sure how my brain came up with all of these

One possibility might be I have been dealing with exponential towers recently

and exponentiation is only right associative

bwDraco

Why is somebody digging through the transcript to flag messages containing "s---" posted by @TheGreatDuck?

None of the messages were overtly offensive.

chat.stackexchange.com/transcript/message/37544446#37544446, chat.stackexchange.com/transcript/message/37554253#37554253

These messages were two weeks old.

Dodsy

beats me.

@Secret John Nash I believe said that math ideas came to him in his dreams.

And Srivnasa Ramanujan said that a God whispered his ideas to him.

Secret

12:49 AM

Well if that's the case, then I am many times Kekule, John Nash and Ramanujan. I have dreams for 6 years and nearly every night, and roughly every 2-3 month there are trippy dreams like these

Dodsy

@bwDraco Guy is probably flagging his own content. People around here think he's been flagging a lot of comments and I think he might be trying to get the heat off of himself, perhaps. Who knows.

bwDraco

@Dodsy The better way to do this is to use a mod attention flag.

Dodsy

What's that?

Avery

you can't self flag

bwDraco

Whoever is flagging these messages, please stop. They're not offensive solely because they contain profanity. They're not meant to be offensive towards anyone.

17

May 23 at 19:49, by Catija

To whomever is flagging things in this room - There is nothing wrong with flagging posts but if you flag something that looks innocuous on the surface, all you're doing is making people distrustful of flags. Please if you have a reason to flag something like this, it is very helpful if you instead use the "Flag for moderator" option and use the explanation field to let us know why you are flagging.

3

Avery

12:52 AM

also smh modflag length limit

Dodsy

I really am not sure, I am just speculating. In fact he's gotten several users banned here due to his flagging, including myself last night.. I really don't know who flagged those posts, or why they would waste the time to go through transcripts to flag every post where he used the word "shit".

Semiclassical

There's been a lot of garbage flagging lately, in this room at least.

Dodsy

You know those twins from 22 jump street?

They sat behind my dad on a plane!

I am related to someone who sat within 5 feet of a famous twin.

Semiclassical

Now I'm just waiting for that to get flagged for using s***. :/

Dodsy

Good point.

Avery

12:55 AM

@bwDraco also, I was recently warned by a mod to not dive into a room and "lecture" users about flag use. Apparently we're just supposed to modflag. just letting you know, because getting warned is annoying.

Meow Mix

Well that's shitty.

nitsua60

@Avery what's up? (I.e. I don't quite understand the action you hope will result from the flag?)

bwDraco

9 mins ago, by bwDraco

Why is somebody digging through the transcript to flag messages containing "s---" posted by @TheGreatDuck?

Avery

@nitsua60 I believe that it's a targeted attack as only that user's messages containing that word was flagged, and the room saw the messages as OK at the time, so I believe that there's an apparent flag abuse.

nitsua60

@Avery Okay, lemme do some digging. [rummages]

Meow Mix

12:57 AM

hi mr moderator

Dodsy

It's been a problem on this chat for some time.

Semiclassical

There's been a lot of flags on this chat which, in my judgment, have been garbage.

Avery

@Dodsy this

nitsua60

Okay, hang on a sec. I'm a Bear of Very Little Brain. Should I go rummage first, or converse? (I'm happy to do either. Or both. I just can't do them both at once.)

Dodsy

I was banned last night for using the word "titty".

Semiclassical

12:58 AM

I say this as a 10k user who does see those flags when they pop up, though I don't have a record of them.

Avery

^

bwDraco

11 mins ago, by bwDraco

http://chat.stackexchange.com/transcript/message/37544446#37544446, http://chat.stackexchange.com/transcript/message/37554253#37554253

Avery

@nitsua60 I feel like there has been ~~some~~ a lot of flags from this room (not a regular, but as a 10k user), ~~sometimes~~ usually incorrect, and posts were made about it before. You're the mod here, but I feel like it's time for "rummaging", as conversing has proven not to be helpful.

Dodsy

@MeowMix what does your homework usually entail for mathematics? i remember when I was in grade 8 it was a lot of word problems. Like sally bought six apples etc etc.

Meow Mix

proofs usually

Dodsy

1:00 AM

Is that part of the curriculum there, or how does that work?

Does the teacher assign you homework that your peers don't work on?

Or are you in a gifted program.

nitsua60

@Avery [rummages to investigate specific concern of one speaker being unduly targeted]

Avery

I don't remember if this one user is being targeted (am drunk and brain is mushy), but this room in general raises a ton of flags.

Dodsy

No, in fact the community beleives that this one user is targetting all other users.

Semiclassical

Ehhhh.

I'll admit I've had my suspicions, but I wouldn't call it a community opinion.

Dodsy

Well, last night he certainly was the one who issued my flag, and he also orchestrated two of Balarka Sen's bans, culminating in him pretending to be Balarka Sen in a seperate chatroom where an I.P address was visible, notifying the chat admin that the I.P of the user pretending to be Balarka was from Indiana.

Meow Mix

1:04 AM

who, duck
?

Semiclassical

...

Meow Mix

@Dodsy

Dodsy

Upon asking Duck if he was from indiana he declined

bwDraco

We may need a CM here at this point.

Dodsy

A search of the transcripts showed that he admitted to being from Indiana.

Avery

1:05 AM

@bwDraco initiate protocol shog

Semiclassical

Yeah, this is well beyond what I'm in a position to make judgments about.

user4704

If you feel like users here are abusing flags in this chat to get other users automatically suspended, you should involve your site's mods.

nitsua60

@Semiclassical Are you RO?

ArtEze

No fight.

Dodsy

Anyways, I'm off, I gotta do homework.

Semiclassical

1:05 AM

I don't know what that is, so I'm going to say no.

nitsua60

Sorry--room owner

Semiclassical

nope.

No idea who the room owner is, if I'm honest.

user4704

As they will have a better ability to examine the flags as they happen.

Avery

room has 4 ROs

3 are mods.

user4704

The user "anon" is a room-owner here.

Avery

1:06 AM

sigh

@JoshPetrie I am not a regular. I don't know this site's mods. Hence, I modflag. I hope that's not a problem.

user4704

chat.stackexchange.com/rooms/info/36/mathematics should show you, unless that view is mod only, but I don't think it is.

nitsua60

If your room owners aren't generally present, aware, and helping moderate chat, that's another point to discuss with your site moderators, in my opinion.

Avery

@JoshPetrie it's not.

Semiclassical

Yeah, I can see the room owners as well.

user4704

@Avery Not a problem; they're just better able to handle it.

user4704

1:07 AM

If it's a systemic issue, I mean.

ArtEze

Pi is exactly 3. (Simpsons)

nitsua60

Either the RO need to step up, or those who are present and engaged need to actually be the room owners.

Semiclassical

@ArtEze Heretic! (Note: Not actually offended.)

ArtEze

-_-

Meow Mix

why the long face?

ba dum tss

because its

nevermnind

Semiclassical

1:10 AM

@ArtEze My actual rebuttal should probably be this: youtube.com/watch?v=Q9-DtuCkRpo

user4704

Anyway, after my perusal of the specific flagged messages, I think the flags were unwarranted (especially given the time elapsed since the messages were sent) and I have revoked the automatic suspension that was applied to the user as a result.

ArtEze

@Semiclassical XD

user4704

And with that, I depart.

Avery

@JoshPetrie can you notify mods of this site?

Semiclassical

Thanks. We'll try to sort things out.

ArtEze

1:12 AM

i m moderator SO in spanish.

nitsua60

Okay, digging one layer deeper... some currently in this room think a flag-harassment program is being waged by whom? Or against whom? I lost the thread.

bwDraco

I've reached out to Community Managers. Hopefully, we'll get a response soon.

in Tavern on the Meta on Meta Stack Exchange Chat, 2 mins ago, by bwDraco

@Shog9, @bluefeet, @AdamLear, @JonEricson: Can somebody look into some suspicious and anomalous flagging behavior in the Mathematics chatroom? The moderators are unable to determine what's going on

Avery

uh

nitsua60

@bwDraco well... we don't know if the mods have tried?

Semiclassical

I wouldn't go that far. All I can attest to is that, since I became a 10k user, I've seen a lot of flags being raised that are frankly silly.

Avery

1:13 AM

@nitsua60 in that case CMs will let mods take over.

bwDraco

This is not the first time we've gone through this. Mods and ROs have not been able to pin down whoever is doing this or why.

Semiclassical

But, I only just recently became a 10k user, so I'm not sure how new that really is. And while I may have my suspicions as to what's behind that, I don't have any evidence of such. Moreover, I'm not a mod or the room owner and really can't do any more than just mark the flags as (in)valid.

nitsua60

@Semiclassical Is it your experience, in this room, that people can productively and frankly talk about messages that bother them?

Avery

I've got 10k around 6mos ago

the number of flags in this room have got much higher in the last couple months

Semiclassical

Well. I'll just say that most of the flagged messages haven't been discussed at all.

nitsua60

1:15 AM

Okay, so to me that could be a couple of things...

Semiclassical

A lot of the time it just has been that a profanity will get used idly, and then a bit later it'll get flagged.

nitsua60

~~(a) someone's abusing flags, out of a vendetta against a particular user (which theory I think I'm hearing)~~

Avery

I try to open transcript and get some context before voting, and even if that takes 15 seconds, the post's review ends. People need to be more careful with voting.

nitsua60

(b) someone's trolling

(c) someone's catching up on the transcript asynchronously and is trying to indicate to this community what they think is acceptable or not

Avery

Those flags were all unwarranted, even with context, but they got validated.

Semiclassical

1:16 AM

I was somewhat closer to (b), but I frankly don't know.

Avery

but why just one user's posts was flagged, then?

Semiclassical

It's not just been one user, in my recollection.

Not one user consistently, at least.

Avery

this flags were all to one user

nitsua60

Okay, so strike my (a)

Semiclassical

Eh. I don't remember it that specifically. I will note, though, that it has been concentrated against a few of them.

Avery

1:18 AM

@nitsua60 I wouldn't exactly say that. Older ones might not be, but these flags were indeed targeted.

nitsua60

@Avery I don't find that at all informative. The fact that inthe room's history a profanity has been used a lot has little bearing on a chatizen, today, indicating that they don't like it.

Daminark

If the most recent stream is that Duck's messages are being flagged, it seems to be someone getting back at him because many are suspicious of his being a frivolous/trolling flagger

Avery

which is not good.

Semiclassical

I need to head out for now. Hopefully you can all get this sorted.

Avery

you don't steal stuff off a thief.

you use law against them.

you don't flag-abuse a flag abuser, you modflag them.

nitsua60

1:20 AM

Hang on. I see ten flags thrown in this room today, two of which are on messages of Duck's. Is that what we're talking about?

ArtEze

Avery

@nitsua60 check the next message's history.

Daminark

I think an attempt was made to contact someone who said that action wasn't possible due to a lack of hard evidence?

Avery

that's at least 4 flags against this user, all in a timespan of a minute.

Some messages were weeks old, and same word was used countless times between then and now, by different users.

Whatever. I told you (mods) what I know, it's up to you to fix it now. See you all later.

nitsua60

@Avery Whoa. You don't want mods "fixing" this, I think.

Avery

1:29 AM

what exactly is wrong with that word?

nitsua60

Our tools are very blunt instruments.

Avery

Then it's up to CMs to handle.

Which have been informed by bwdraco.

nitsua60

There's something screwy with a room's culture when flags are being thrown and validated, but regulars aren't creating an atmosphere that welcomes discussion of pain-points over flags.

@Avery That's going to go even worse, I'd expect.

Avery

I know what happens when CMs get involved.

And I know what warrants them to be called.

nitsua60

So work toward a room culture that invites open and honest discussion of norms and chattiquette, if you don't want the sorts of tools that (offsite) mods and CMs tend to bring to bear.

Avery

1:32 AM

And when users, ROs and mods have proven useless, I can't say I can argue with what bwdraco did.

nitsua60

(remind me which one draco is?)

Avery

well, useless sounds rough there

20 mins ago, by bwDraco

in Tavern on the Meta on Meta Stack Exchange Chat, 2 mins ago, by bwDraco

@Shog9, @bluefeet, @AdamLear, @JonEricson: Can somebody look into some suspicious and anomalous flagging behavior in the Mathematics chatroom? The moderators are unable to determine what's going on

"ineffective"?

yeah, that's better.

@Avery (thanks)

1:33 AM

no worries.

nitsua60

I'll say, when I see a room where there's lots of flagging and chat-bans... I feel like things have gone wrong well upstream.

Chatizens are rejecting what's going on, but dont feel that using their words is the best way to do so.

nitsua60

1:49 AM

On an unrelated note, I don't feel like grading math exams. But I need to grade math exams. What's your solution to this dilemma?

Daminark

2:04 AM

This is a predicament...

nitsua60

ahh... so you just rename it from "dilemma" to "predicament," eh?
=D

Daminark

Yeah, so it ceases to be a dilemma!

Lol in reality it's probably best that you grade. Your future self will thank you

nitsua60

@Daminark I wish that guy would get off my back--he's always making me eat my veggies and floss and grade. Simultaneously!

Ooh... this one's not going well for student A. I'll tell them it's your fault, it might have remained ungraded one more day if not for you =)

Does this chat accept LaTeX?

\frac{1}{2}

or do you-all just read it fluently?

Avery

2:29 AM

@nitsua60 most users use chatjax

nitsua60

which is?

Avery

math.ucla.edu/%7Erobjohn/math/mathjax.html

Or better, github.com/vyznev/chatjax

nitsua60

$\frac{1}{2}$

gotcha. Thanks!

(This'll make it much nicer when I peruse this room and the h bar!)

Akiva Weinberger

2:49 AM

Yeah, we use a script that renders the math for us. Most of the stuff on here would be incomprehensible without it.

Or, maybe everyone else writes their stuff in a sensible way, such that all the curly braces and so on would help you figure out what it's supposed to be. I generally don't.

Dattier

3:10 AM

hi

$(X^{2^{2^{2017}}} \mod (X^3+2X+1)) \mod (2^{89}-1)= ?$

Dovah-king

Hey guys

i have a very stupid problem here that i can't solve... if someone could help me, it would be great! xD

Zee

Post it and hopefully someone will see it

arctic tern

@Dattier so X^(2^(2^2017)) mod the nonprincipal ideal (X^3+2x+1,2^89-1)?

the 2017 makes that look like a contest problem

Dovah-king

Okay. So i got this matrix (sorry, i can't see mathjax in here):
1 -4
2 -3

And i know that (-1+2i) and (-1-2i) are two eigenvalues of it (here, i^2 = -1).

bwDraco

@Dovah-king math.ucla.edu/~robjohn/math/mathjax.html

Dovah-king

3:23 AM

It doesn't seem to work on google chrome...

arctic tern

it does

TheGreatDuck

@Dodsy why the hell do you accusing me of flagging stuff? I haven't flagged anything. Quit being so rude. I said I didn't do it. Why do you keep being such a jerk? FOR THE NTH TIME,I only flag stuff if it is actually damaging to the site. Once in a blue moon I might intentionally joke with a mod and flag something but then it's very obvious and that was a long time ago.I've been in this chat for years.

Dovah-king

Alright, now i can see it

okay, so i have this matrix:
$\begin{matrix}
1 & -4 \\

ops

$\begin{matrix}
1 & -4 \\
2 & -3 \\
\end{matrix}$
and i'm trying to find the eigenvectors related to the eigenvalue $\lambda_1 = -1 + 2i$

TheGreatDuck

If there really was a flag craze driven by me, don't you think it would've been going on a lot earlier? Plus you said the flags are being validated according to you and I'm not 10,000 rep. So explain how I'm getting these bogus flags passed through? I've not even been on here much lately. I was told to stay out of chat and since then I've been mostly working on my code over on stack overflow or just writing code offline. I'm not flagging, alright? It's probably cause I got banned unofficially...

Araske

@Dovah-king I usually set these up as a linear system

TheGreatDuck

3:29 AM

People are probably trying to report I'm in chat and violating the ban. But excuse me if you people keep messaging me back here. UUUGHH!

Dovah-king

What im trying is this:
let a vector $v = [m,n]$ be the eigenvector related to $\lamba_1$. Then:
$(A-\lambda I)v = 0$
So, since there it will be infinite equations, we can get any equation, i've choosen the first one:
$(1-(-1+2i))m - 4n = 0$
And so:

TheGreatDuck

sorry but that was getting REALLY annoying

arctic tern

@Dovah-king use pmatrix for parenthesized matrices or bmatrix for bracketed matrices

otherwise you just have an array

Araske

so solve $$ (2i-1)x= x-4y \\ (2i-1)y = 2x - 3y$$

Dovah-king

Yes, @Araske

i'm trying to solve this system. Since it have infinite solutions, the two equations are equivalent to each other

so we can choose any of them

let's try with the first:

Araske

3:31 AM

wait there shouldn't be?

hold up

Dovah-king

okay

Araske

arent the eigenvalues complex conjugates?

Dovah-king

yes

they aer

are*

Araske

so you get an equation of $y$ in terms of $x$

Dovah-king

yes

Araske

3:33 AM

pick $x=1$

you find $y$?

Dovah-king

yes

$y = \frac{1-i}{2}$

Araske

and $(x,y)$ is one element of a 1-D vector space, which it spans?

Dovah-king

the line that contains the vector

Araske

sorta?

Dovah-king

the problem is that $v = [ 1, \frac{1-i}{2}]$ is not an eigenvector at all...

Araske

3:35 AM

like, you multiply the vector by any element of $\mathbb{C}$

Dovah-king

according to mathematica, the eigenvectors are: $v_1 = [1+i,1]$ and $v_2 = [ 1-i,1]$

Balarka Sen

@AkivaWeinberger I like this.

Araske

$(1+i) \times (1, \frac{1-i}{2}) = (1+i , 1)$

its "scaled" by the complex number

Dovah-king

why would i do this multiplication before start working with the eigenvector i found?

This matrix relates to a system of differential equations

Araske

they are both eigenvectors

so like

Dovah-king

3:39 AM

and the solution (to the system) that mathematica gave me is totally different from the one i found using $(2, 1-i)$ as an eigenvector...

Araske

if we are working with a vector field over $\mathbb{C}$ we can scalar multiply by anything in $\mathbb{C}$

Dovah-king

yes

Araske

OH this is a differential equation solution

hm. So it's part of the same solution space in some way, but I don't know enough about linear systems of equations...

what are the different solutions?

Balarka Sen

It seems shit happened in the transcript.

Araske

or the original problem

Semiclassical

3:42 AM

@BalarkaSen Quite.

Araske

@BalarkaSen so it seems

Dovah-king

The original problem is:
$x_1 ' = x_1 -4x_2$
and
$x_2 ' = 2x_1 -3x_2$

the solution i found:

BAYMAX

I don't know but rooms seems to be angry here and there allso some starred messages , everything alright ?

Araske

digs out physics notebooks

Balarka Sen

Morning, by the way, everyone.

BAYMAX

3:44 AM

Good morning @BalarkaSen

Dovah-king

$\vec{x}(t) = e^{-t} [cos(2t),\frac{cos(2t)+sin(2t)}{2}] + [sin(2t),\frac{sin(2t)-cos(2t)}{2}])$

btw e^{-t} is a factor of both vectors

Semiclassical

Such problems are of the generic form $x'=Mx$ where $x=(x_1,x_2)^T$ and $M$ is a 2-by-2 matrix.

And as such the usual approach is "diagonalize M."

Dovah-king

i think that the solutions are the same, written in a very, very different way. but thanks guys. i'm going to sleep now, its 1 AM over here. good night, and thank you

Zee

@Semiclassical hey, you up?

Semiclassical

yus

Zee

3:53 AM

You know complex analysis?

Semiclassical

ya

Zee

Ok, this is odd, but I was wondering

What is the weakest condition on a Cauchy rieman equation for. Complex function to be holonorphic?

I.e. We know continues CR functions are holonorphic

arctic tern

continuous

Zee

No, you can weaken that

But by how much?

arctic tern

huh? when you say "continues," what do you mean if not "continuous"?

continues is a verb, not an adjective

Zee

3:55 AM

A complex CR function is holonorphic on weaker conditions than continues

Araske

@arctic typos i think

BAYMAX

Is continues = continuous for you@Zee

Zee

Ya, typo

arctic tern

I really should try knowing more than one language.

So I can be one of these cool people.

if by "continuous CR function" you mean a function which satisfies the Cauchy-Riemann equations, then "continuous" is redundant since to satisfy the CR equations it needs to have first partial derivatives for which continuity is necessary (but certainly not sufficient)

Araske

@zee holomorphicity implies continuity; I believe the existence of the partial derivatives in the CR equationd also requires continuity

Balarka Sen

3:59 AM

@arctictern Well, it's not true that you need continuity to have first partials.

Daminark

That isn't quite true, you can be discontinuous

What is this sniping?

Araske

all partial tho

Balarka Sen

lol

Akiva Weinberger

What is this pointing out of sniping?

Transcript for

$Mathematics$ Mathematics