Mathematics

6:10 PM

Hey guys, what's the QPD over here on Math.SE? Seems incredibly high just looking at the question feed.

it's high

user147690

It's probably not constant valued, but we can give an average?

yesterday's looks to be approximately 800

Wow, that is high. Thanks, I was just curious.

@Owatch source?

6:14 PM

I know that Area51 shows basic stats like QPD for beta sites. Is there anything like that for graduated sites that you know of?

user147690

Yep, you can even run your own scripts on the data.

user147690

data.stackexchange.com/math/queries

@mike going to a symplectic topology seminar today. fingers crossed that i get something out of it :P

what's it about

user147690

Data on all of the graduated exchanges probably @JPhi1618 data.stackexchange.com

user147690

6:15 PM

Oh there you go

user147690

Looks like all exchanges in general, graduated or not

something on dehn twists

user147690

There you go data.stackexchange.com/math/query/14647/…

user147690

Number of questions per day

@AlexClark, Thanks! I'll have to check out some queries to see how that works. Looks very interesting.

6:18 PM

"Let $[G,G]$ denote the commutator subgroup of a group $G$. For $x$ in $[G, G]$, we define the commutator length $cl(x)$ of $x$ to be the smallest number of commutators in $G$ whose product is equal to $x$. The stable commutator length $scl(x)$ of $x$ is the limit $scl(x) = \lim_{n \to \infty} cl(x^n)/n$. By providing explicit factorizations of powers of Dehn twists as products of commutators, we give a new upper bound on stable commutator lengths of Dehn twists."

if they didn't say something like "generalized dehn twists", it's probably about surfaces

yeah, that's goign to be about mapping class groups of surfaces

sounds interesting tho

i probably won't understand much of it

Can anybody think of an unordered basis $\{ x_1, \dots, x_m \}$ where $(x_1, \dots, x_m)$ isn't a basis?

do you know what a dehn twist is?

I've been trying to get my head around these but I have no idea what's going on.

6:20 PM

@Kari An unordered basis is precisely a set of vectors that form an ordered basis if you order them

topologically, yeah

that's all this talk will be

That's what I thought but my set of lecture notes suggests that we find an example of such an ordered basis, @TobiasKildetoft. :-/

mmkay. i know about them from how riemann surfaces transform under monodromy

It's impossible, right?

6:21 PM

@Kari Yes, unless they define things in weird ways

'mapping class group' isn't a term i'm familiar with, though, so :/

If $X$ is independent and spans $G$ (where $X \subset G$) then $X$ is an unordered basis.

That's how it's been defined for me, @TobiasKildetoft.

What is it with people and their need for questions to have "context"?

This doesn't make sense to me.

@TheGreatDuck There are good reason to require context

@Kari Right, then it is not possible

i'd chalk it up to "need for questions that aren't homework"

user147690

6:23 PM

@TheGreatDuck Example question that you disagree with concerns over context?

or, more charitably, questions where, while motivated by homework, the poster has clearly done a certain amount of due diligence

Like what? I mean one could try to use it to prove somethings not homework, but context doesn't show anything about homework issues.

user147690

I don't see how it is hard to provide context

@AlexClark There's tons of questions with 5 or 6 answers where the post has been closed.

@TheGreatDuck context also provides the information necessary for people to figure out what sort of answer will actually be helpful

user147690

6:25 PM

How could one be unable to write any context?

But context says

""This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – RecklessReckoner, T. Bongers, Harish Chandra Rajpoot, Shailesh, Claude Leibovic"

"any attempts you have made to solve it"

@Semiclassical diffeomorphisms form a group, right?

@TheGreatDuck Yep, that is a good explanation of what should be there

so, everyone is required to have tried solving before asking?

that makes no sense

user147690

Well I would certainly hope so

6:26 PM

i mean sure, there are obvious silly cases.

like arithmetic

user147690

Not just for our sake, but the students sake

"but for the students sake"

@Semiclassical mapping class group is (as far as I recall) just diffeomorphisms modulo isotopiy

yet see this question math.stackexchange.com/questions/1597999/floor-functions

how is that homework under /any/ circumstances?

user147690

It's not about being homework. The question is pretty bad

6:28 PM

@TheGreatDuck How could you ever think that would be anything but homework?

Floor function isn't used in classes anywhere

lol

@TheGreatDuck Of course it is.

and it certainly isn't anylized graphically

@TheGreatDuck Once again, yes, of course it is.

6:29 PM

OP is probably truly and honestly inspired by the beauty of the floor function

^

besides

it's got 5 answers

user147690

LMAO @MikeMiller

@TheGreatDuck That is a terrible reason to keep a question open

user147690

Honestly I doubt it isn't a near duplicate

it's already been answered and accepted. It's clearly a decent question. Otherwise it wouldn't be answered.

user147690

6:30 PM

On top of being bad

how is it "bad"

it asks a question

short and simple

user147690

I mean even the title was without thought

user147690

"floor functions"

Ok I suppose that wasn't the best choice.

but the question itself is clearly understandable.

@TheGreatDuck That is not what makes a good question

6:32 PM

But you have yet to say what makes it a bad question.

it's unclear to me why either side of this argument is engaging with the other

@MikeMiller Good point

Excuse me?

Are you trying to say I'm out of line.

no, i'm saying neither of you are going to convince the other

user147690

He's saying neither party will change their mind

6:33 PM

oh

it wasn't meant to be an argument

i was just asking why questions that have already been answered are getting closed

that doesn't make sense

the purpose of closing is to reject a question from th site

user147690

Bad title, doesn't show any attempt, doesn't provide any information of what they actually don't understand, doesn't give us any motivation to even help them, doesn't give a good example for what a question on the site should look like

"doesn't give us any motivation to even help them" since when does an asker have to justify getting their question answered?

since the introduction of closure and deletion buttons :)

2

user147690

If you are going to single out one point, and ignore the rest, that isn't really reasonable

the purpose of closure and delete buttons is to remove content that is innapropriate, not just some question you don't think is worth answering.

user147690

6:36 PM

Anyway I have to get back to work, read the rest of my points

user147690

Gives us motivation to even help them is probably sufficient not to be closed was how you should of read that

"Doesn't show any attempt" this is a Q&A site. There's no reason a person needs to give an attempt. They ask and get answered. Nothing more, nothing less.

@TheGreatDuck Except this is not just some Q&A site (to see why this is a good thing, spend a bit of time on Quora)

"doesn't provide info on what they don't understand" Ok, that I can see, but that depends. One shouldn't need to include that in an answer.

@TobiasKildetoft Fair enough. It's just weird to see people targeting well trafficked and up-voted answers with closures for no context. After all, the best metric of a question is whether or not people were able to effectively answer it. If it was, then there's no real reason to mess with it.

@TheGreatDuck No, that is not a good metric for quality at all.