Mathematics - 2015-11-12 (page 2 of 4)

Because if I just add $\pi$ to all of the negative values I get from using the $\tan^{-1}$ formulas, there's no chance that $\theta_1 > \pi$, you know?

Soham Chowdhury

well, do you know all the other $\theta$s?

Clarinetist

3:06 AM

Yes, because in order for me to find $\theta_1$, I have to know the other $\theta_i$ using the recursive relationship

Soham Chowdhury

@Clarinetist I didn't get that last sentence.

@Clarinetist then find $r$!

use that to find $\theta_1$.

assuming I'm not confused here, that should work

Clarinetist

@SohamChowdhury Hmm... that's a thought. But doesn't that lead to the same problem, since $\cos^{-1} \in [0, \pi)$?

Soham Chowdhury

is this your problem?

wolframalpha.com/input/?i=arccos+%28cos+%282pi+-+0.0001%29%29

I don't think it matters, then. your program will give you a different $\theta'_1$ instead of $\theta_1$, but they'll have the same $\cos$

hey @anon.

anon

hey

Soham Chowdhury

sup?

Clarinetist

3:13 AM

@SohamChowdhury That's what really bugs me about this assignment. It's not clear how he actually expects us to find $\theta_1 \in [0, 2\pi)$.

Soham Chowdhury

I'd quit worrying about it tbh

he probably won't care. you're in a stats program, for heavens' sake. /s

Clarinetist

This is the first assignment that I've had in this class that has made me glad to have taken analysis and algebra in my undergrad. One of the previous problems required coding the Euclidean Algorithm

Soham Chowdhury

I'm around halfway through learning Clair de Lune, btw. :)

Clarinetist

@SohamChowdhury Congrats, that piece is tough

I wish I had a piano and the technique to play that

In a year or so, maybe

at least the piano

Soham Chowdhury

My calluses agree, although it's hard on guitar because of the fast arpeggio-ish middle part.

That's where I'm going slowly.

Clarinetist

3:16 AM

Omg, you're trying that on guitar?

Soham Chowdhury

Yes!

Clarinetist

I forgot, heh. It's been too long

Props

Soham Chowdhury

Sounds beautiful, actually. This arrangement.

Debussy, Clair de lune, guitar solo, James Edwards

►

The harmonics are fun!

Clarinetist

listening

Karim Mansour

I see how I can solve it now @TedShifrin given the hint

I will just proof the hint first

and then I will mention how I did it

Clarinetist

3:18 AM

Is this in the original key?

Karim Mansour

actually here is how to do it

so the part c mentions that

Soham Chowdhury

it's in D

half-step up.

Karim Mansour

Show that $R^{\omega}$ the box topology. Show that x and y lie in same component of $R^{\omega}$ iff the sequence x - y is "eventually 0".

so if we assume this is true

Clarinetist

Doesn't make it much easier :P

Karim Mansour

consider a representative of a particular component

write that representative as follows

Soham Chowdhury

3:20 AM

we guitarists seem incapable of playing outside E, B, D, G, and A (roughly in that order)

Karim Mansour

$x = (x_1,x_2,.......)$

Clarinetist

@SohamChowdhury Given what I know of orchestration, that's pretty much true for any string instrument player :P

Soham Chowdhury

I also learned Take Five (and how to swing, in the process).

Karim Mansour

consider $y = (|x_1| + 1,|x_2| + 1,|x_3| + 1,...)$

Soham Chowdhury

That is one fun piece to play.

Clarinetist

3:21 AM

I am sharing this arrangement. Very neat

Karim Mansour

so x - y is never eventually zero

so it can't be in same component

Soham Chowdhury

Okay, I have got to start working now.

Karim Mansour

so since we can do this for every representative of equivalence class

Soham Chowdhury

I assume you've heard Take Five?

Karim Mansour

we can see that $R^{\omega}$ has infinitely many components

Clarinetist

3:22 AM

Oh, of course

Soham Chowdhury

heh

This arrangement is amazing, more so because of the faces the guy makes.

Paul Desmond 'Take Five' Arranged for Solo Guitar by Steven Brennan

►

I play this one, though.
It's not too hard, although I learned the solo on my own.

Take Five - Solo Guitar Arrangement - Chet Atkins

►

Clarinetist

OMG that looks difficult

morphic

can you play that on the clarinet @Clarinetist

Clarinetist

The thing is, when you're playing clarinet, you can only play one line at once. :P I likely could

PerplexedGuest

3:48 AM

Hello all! :)

FizzledOut

Hello

Simeon

If I want to minimize the distance between two implicitly defined surfaces, can I just find the points at which their gradients are parallel?

Ted Shifrin

@Simeon: It's more than that !

@Karim: Sounds like you're just assuming what you're trying to prove. I've thought about it during dinner, and Munkres's hint is exactly right. You need to look at $x$ all of whose components are bounded and $y$ whose components are unbounded.

Simeon

But that's how you would find the critical points to start with, isn't it?

Ted Shifrin

Critical points of what? This isn't Lagrange multipliers, unless you set it up as Lagrange multipliers.

Simeon

3:59 AM

Oh you're right, there's no reason why they would have to be parallel.

Ted Shifrin

No, they have to be parallel, but you need more.

Draw a picture ... when you have the closest points $x,y$ in $X$ and $Y$ respectively, what does your picture look like?

Simeon

oh yes, opposite directions

Ted Shifrin

Hmm, not necessarily ... you don't know which direction the gradient points. What about the line segment joining $x$ and $y$?

Simeon

it is normal to both surfaces?

Ted Shifrin

There you go.

Simeon

4:04 AM

But why?

Ted Shifrin

Think about the Pythagorean Theorem. If the chord isn't normal to both surfaces, you can move the point(s) to make the distance shorter.

Simeon

Hmm, is there an explanation similar to the Lagrange method (if we use the chain rule for some curve to show orthogonality)?

Mike Miller

Equivalently this comes back to the bit you were thinking about earlier w/ finding critical points... if you fix a pt v in one of the surfaces the closest point in the other surface to it must have w-v perp to the surfaces. why? minimize the fctn $f(w) = \|w-v\|^2$

Ted Shifrin

Yes, @Simeon.

@Simeon: If you have learned about Lagrange multipliers with more than one constraint, you can also set this up as a Lagrange multipliers problem with $x$ satisfying $g(x)=0$ and $y$ satisfying $h(y)=0$.

Of course, if these are surfaces in $\Bbb R^3$, you'll end up with $6$ variables, $2$ constraints.

Simeon

Oh ok, but what is the function that I have to maximize?

Mike Miller

4:09 AM

minimize

Ted Shifrin

$f(x,y) = \|x-y\|^2$.

Simeon

yes

Ted Shifrin

Didn't mean to step on your toes, @MikeM.

Mike Miller

you're not

: - )

Simeon

Oh that makes sense now, thinking about it as a Lagrange problem

Ted Shifrin

4:12 AM

If you work it out, it'll tell you exactly the geometry we had: That the chord joining $x$ and $y$ should be parallel to both gradients.

Simeon

In general, when using Lagrange multipliers, and you get only one point as a solution, how can you verify using the Hessian whether it's a max or a min?

Ted Shifrin

The Hessian test for constrained max/min is very subtle. I doubt you're expected to do this. You can find the test in Marsden/Tromba or my Multivariable Math book.

Simeon

Oh ok, so I should probably use another argument, like finding another point that's smaller / larger

Ted Shifrin

Besides, the second derivative tests only prove (if you're lucky) local max/min. You need some global arguments (e.g., compactness) to know there is a global max/min.

What sort of course are you taking?

Mike Miller

@Simeon: You really just need to know some things about lengths of triangles to prove that the chord is perp to the surfaces.

Simeon

4:19 AM

Analysis II using Munkres Analysis on Manifolds

Ted Shifrin

I did make reference to Pythagoras at the beginning, @MikeM.

Mike Miller

The surfaces aren't flat... it's not quite pythagoras

Ted Shifrin

Ah, ok, so you should make some sort of global compactness argument or something, @Simeon.

Yes, of course, @MikeM.

Mike Miller

Tried to give this arg to my multivar calc students (for curves). They did not like it so much. So I just went back to the second deriv test...

Ted Shifrin

If your surfaces are compact, then you're guaranteed a max/min.

PerplexedGuest

4:20 AM

@TedShifrin - you're a mathematics professor, correct? :0

Ted Shifrin

I was once, @Perplexed :)

PerplexedGuest

Ah, okay. It's cool to know that someone of your math level chats here.

I often wonder what professors/former professors do math-wise in their spare time. xD

Simeon

Oh my you're actually that Ted Shifrin,

I'm honoured

Ted Shifrin

LOL @Simeon, whatever that means.

Simeon

I remember watching your lectures recently, they were very helpful

Ted Shifrin

4:22 AM

Ah ...

Soham Chowdhury

Ted, while I'm aware of the fact that you don't like Hubbard/Hubbard, would it be absolutely unworkable for me in your opinion?

Hmm, that's a thought. I could always watch your lectures.

Ted Shifrin

I can't answer that, @Soham. I don't know you well enough, and lots of people love the book. I just find it too idiosyncratic and the exercises not systematic and helpful.

When I first created the multivariable math class back in 1998, I used Hubbard/Hubbard as the text, and just gave up in the middle and started writing my book. My students weren't finding it helpful.

Soham Chowdhury

Oh.

Ted Shifrin

To me, exercises are the most important thing about any math text. Of course, Jasper disagrees.

Soham Chowdhury

Well, do you know any place I can find nice exercises?

Hmm, especially books that have "guided proofs" in the exercises.

I like those a lot.

Ted Shifrin

4:26 AM

No, most multivariable books are computations with no proofs.

Mike Miller

what's your goal?

Ted Shifrin

Soham, couldn't you wait and learn this when you get to university?

Soham Chowdhury

Knowing IFT, pretty much. I want to look at manifolds.

bolbteppa

You should watch the videos, I watched the pullback one a long time ago and really liked it

Soham Chowdhury

I could, @Ted.

Ted Shifrin

4:27 AM

The Inverse Function Theorem is sophisticated enough that most undergrad math majors in the US never learn it. I don't know why you high school people think you should be learning it.

Soham Chowdhury

But I sort of want to learn as much as possible before, because I have a terrible fear of being swamped in linear algebra homework.

Mike Miller

@TedShifrin this is more a corollary of poor instruction/syllabi imo.

Ted Shifrin

Take your time. Good grief.

No, @MikeM, it's a consequence of the fact that we have people majoring in math who don't want to be mathematicians. And I'm ok with that.

Mike Miller

my undergrad had an 'advanced calc' class (mandatory for math majors) that somehow did not cover it.

Soham Chowdhury

That's why I'm not looking for a five-page ultra-concise treatment of the theorems, @Ted. I want to learn multivariable calc, properly. And that should include those theorems, from what I've heard.
That's all.

Mike Miller

4:29 AM

they ousted the prof who had been teaching it for decades and rewrote the syllabus so that the people who take it now learn some calculus.

Ted Shifrin

Well, except for the really talented ones and ones who want to go to graduate work in math, the math major has lots of other focuses and ...

Soham Chowdhury

Is it so bad that I want to learn multivariable now? I don't get it.

Ted Shifrin

Sometimes good teachers/professors actually help you learn. All this self-study is not for everyone, even though you kids are obsessed with it.

Only a handful of my students at UGA, with my mediocre instruction, were really able to learn it deeply. The rest of them learned computations and had some vague idea about the theory. And that was typically a class with 25 students.

Forever Mozart

i'm baaaaack

Ted Shifrin

That's too social of you, @Forever :)

Karim Mansour

4:32 AM

@TedShifrin I am tired atm I will think about it tomorrow

Ted Shifrin

It's subtle, @Karim. Not an easy exercise.

Karim Mansour

yeah

Forever Mozart

well I drank 2 beers so I'm too social now

Ted Shifrin

LOL @Forever

Mike Miller

save one for me

Forever Mozart

4:33 AM

haha

Mike Miller

or five

Ted Shifrin

I wonder what time zone Forever is in ...

Forever Mozart

central time

Ted Shifrin

ah, so getting later ...

Karim Mansour

lol what time zone forever is in

sounds funny

considering the nick name

Ted Shifrin

4:35 AM

If I'd put the @ in there, @Karim, you wouldn't laugh :D

Karim Mansour

yeah haha

Mike Miller

seems a bit late to be having your second beer

Ted Shifrin

it was his second, @MikeM ... pay detention.

Mike Miller

all the same ;)

Forever Mozart

when I have even one beer my ability to do math goes way down

Soham Chowdhury

4:36 AM

okay, @Ted, so what should I be doing in your opinion?

Karim Mansour

anyway good nights guys

Forever Mozart

but with coffee it is opposite, for a short time

Karim Mansour

cya tomorrow

Ted Shifrin

Soham, I don't know you. It's not my business to schedule your life. I don't know your abilities or your depth of understanding of what you've learned.

Cya, @Karim.

Soham Chowdhury

Well, that's true.

Ted Shifrin

4:37 AM

But, generally, I see a ton of people in this chatroom trying to learn stuff that's above their level to really understand and learn deeply.

I see some people in college doing that, too ...

Soham Chowdhury

Hence the exercises, @Ted. I am wary of learning half-baked stuff.

Ted Shifrin

So, @Forever, what's the story of the moral?

Forever Mozart

lol

PerplexedGuest

People love biting off more than they can chew.

Ted Shifrin

But exercises without someone grading them aren't necessarily magic, @Soham.

See, @Forever, you do have a sense of humor :)

Oh, the beers do.

Soham Chowdhury

4:39 AM

That's why I come here, @Ted. Tons of people to ask.

Ted Shifrin

Not the same, @Soham, not the same.

Soham Chowdhury

And usually it's one of "how does one even do this problem?" and "ohh, let me write it down, I see how it should be done" for me.

Well, I know a prof whom I go to very infrequently.

Ted Shifrin

Most of my (talented) college students, even when they think they've written a good argument, get back lots of red from me.

I'm just in favor of slowing down and building really strong, deep foundations.

Forever Mozart

Thursdays are my day off, so usually I try to prove some things Wed. nights. But, at this point I got all the low hanging fruit. The only thing left is the big conjecture which is not going to be easy...

Ted Shifrin

What kind of stuff do you work on, @Forever?

Forever Mozart

4:42 AM

connected topological spaces

Ted Shifrin

That's a bit vague.

Soham Chowdhury

spaces that go on forever

Mike Miller

i'm into those

Soham Chowdhury

@TedShifrin I don't think anyone in their right mind would disagree, @Ted.

Forever Mozart

it's vague, but I'm interested in lots of different types

Ted Shifrin

4:43 AM

So you're aiming to do a thesis on point-set topology, @Forever?

Forever Mozart

different types of local connectedness, compact connected spaces, etc

yes that's what I'm trying to do

Ted Shifrin

OK ... my impression is that what's left to do is very technical and very arcane.

Mike Miller

@SohamChowdhury consciously, no, but there are plenty of people who claim to be in favor of that whose actions don't at all line up with it, and don't take advice from people who point this out to them

(i'm not referring to you.)

Ted Shifrin

@MikeM is referring to Balarka in his former existence, for example.

Soham Chowdhury

I get the feeling I'm being tiresome now, so: do you have any suggestions for where someone can learn multivariable from? I want to do it slowly, as you say, but also learning the "big theorems" properly. And I've worked through a book before, but it was not at all rigorous.

Me, too, about two months back.

Forever Mozart

4:45 AM

yeah, what's left is very technical and mostly with non-metric spaces

Ted Shifrin

Oh, definitely, non-metrizable spaces, @Forever.

Mike Miller

is there non-technical math left?

Ted Shifrin

Yes, @MikeM

Mike Miller

maybe I should change my field...

Soham Chowdhury

In the past week I've basically cleared out most of Artin's exercises from three chapters of linear algebra. Never would've done that before.

Ted Shifrin

4:46 AM

Number theory still has stuff that can be readily understood.

Soham Chowdhury

Which is why it attracts the cranks?

Ted Shifrin

Not so readily solved.

Everything attracts cranks.

Mike Miller

sure... by math I didn't mean the statements of hte theorems, I meant the stuff one does

:)

Ted Shifrin

Fair enough, @MikeM.

Forever Mozart

by technical I mean a lot of current research in topology is tied to various weird set theoretic axioms

Mike Miller

4:46 AM

but certainly I can think of stuff that's not so hard in my area i guess

Ted Shifrin

Yup, @Forever. This is stuff that's never appealed to me, so I haven't at all kept track of where research is.

Soham Chowdhury

Well, I'll go ask on main. See ya, everyone.

Ted Shifrin

bubye @Soham

Forever Mozart

it can be very abstract and semantic

like set theory

Ted Shifrin

yup

Mike Miller

4:49 AM

@SohamChowdhury: I don't think anybody is frustrated with you personally. It's hard to give personal advice when you don't know the person, and it sounds like there's not really a good place to learn all the stuff we're talking about.

Good luck with your question.

Ted Shifrin

Well, @MikeM, Hubbard/Hubbard and my book are the two common sources these days. But mine, at least, is expensive.

And I'm not going to provide free copies to everyone in here.

Forever Mozart

there are still lots of open problems: carma.newcastle.edu.au/jon/Preprints/Books/…

Mike Miller

open problems about open sets

Forever Mozart

yes

DanielSank

Hi, everybody. I'm learning stochastic processes by solving the problems in Van Kampen's book. If anyone's interested, join in the work here.

Forever Mozart

4:59 AM

what is github?

DanielSank

@ForeverMozart It's a free graphical interface to a git repository with a lot of features which make working with other people easier.

Do you know what git is?

Forever Mozart

no

DanielSank

@ForeverMozart Ah.

Forever Mozart

I have used overleaf before

for collaborating

DanielSank

@ForeverMozart I'm pretty sure overleaf uses git under the hood.

Or maybe not.

In any case, they serve similar purposes.

Forever Mozart

5:02 AM

multiple people can edit the latex file

DanielSank

@ForeverMozart The idea with git is that everyone has their own version controlled repository of all files. I can change my files without you knowing anything about it. Then, we can merge our respective changes together when we choose to do so.

Github provides some nice user-interface stuff to make that merging process easier.

In fact, can can use github without knowing anything at all about git. You can do your editing online. Github doesn't render TeX like overleaf does though.

It's mostly for programming code.

Wait, what the heck? @ForeverMozart overleaf uses a "secret link" to keep your work private?

You can't set user access permissions?

Forever Mozart

yes

you share it with people you want

DanielSank

Oh I see, it supports both. There's a "secret" (LOL) link and user access permissions. That's good.

Looks nice.

Forever Mozart

yeah it is very easy to use. we used in in a graduate class. the professor listed theorems and assigned them, and we all typed in our proofs

DanielSank

Looks great. One thing I like about github is the ability to file "issues" which are resolved by subsequent work. Does overleaf have something like that? Some kind of "todo" support?

The idea of "issues" is to collect discussion and work focused on resolving a single problem or adding a single new feature.

Forever Mozart

5:12 AM

i don't know too much about that. You can create a project and have multiple tex files in it

I doubt I have used all their features

DanielSank

ok, thanks.

cp101020304

prenex normal form If someone could help me with this simple question, I would appreciate it. It is regarding free variables when converting to prenex normal form. Thanks

PerplexedGuest

6:00 AM

Lol this is truly nasty.

2

Q: Why is this sum equal to $0$?

While solving a differential equation problem involving power series, I stumbled upon a sum (below) that seemed to be always equal to $0$, for any non-negative integer $s$. $$ \sum_{k=0}^s \left( \frac{ \prod_{r=1}^k (-4r^2+10r-3) \prod_{r=1}^{s-k} (-4r^2+6r+1)}{2^s (2k)! (2s-2k+1)!} \times (2s-...

sequences-and-series

Soham Chowdhury

@DanielSank nope, AFAIK

PerplexedGuest

I really wish there was a way to depict 4-dimensional objects. >:(

We could embed them onto a 3 dimensional space much the way we can embed 3 dimensional objects onto a 2 dimensional space, couldn't we?

DanielSank

6:45 AM

@SohamChowdhury That's too bad. The built-in issue tracker on github is one of it's best features.

@PerplexedGuest When you represent an n+1 dimensional thing in n dimensions, you're not "embedding" it, you're "projecting" it.

And sure, you can project 4D objects in 3D.

Here's an example.

skill patrol

8:23 AM

@robjohn would you mind having a look at this question please?

TanMath

man @skillpatrol you are up so late! I caught you on your desktop! yay!

skill patrol

@TanMath Hi pal :-)

yep, laptop actually :P

I think desktops are going to go the way of the dinosaurs.

I only use mine because of the printer...

Tien-Cheng Huang

Could someone help checking if there is a fallacy in this exercise? i.imgur.com/0gmPCEP.jpg My TA said he don't understand this proof.

Could someone help checking if there is a fallacy in this exercise? i.imgur.com/0gmPCEP.jpg My TA said he don't understand the notation $N_{\epsilon}(a)$ in this proof.

rene

10:30 AM

Would this question posted on SO be on-topic on math.se?

skill patrol

yes

rene

10:45 AM

OK, I'll flag for a mod to get it migrated then, tnx

Soham Chowdhury

@DanielSank yep, I know

Alec Teal

12:13 PM

You know when you do a } under something, how do you do that?

So you can say "this part of the expression is" and put a } under the part to show you mean this part.

Boni

@AlecTeal This thing?

Alec Teal

Did you have to edit that 3 times? Can't you just write it out?

Boni

Bad typos, sorry. Does each edit send a ping?

Alec Teal

It does. Also it isn't that helpful.

It would have been faster if you'd just said \underline thanks for trying though

Boni

I didn't know that. I wouldn't have done it if I did. Apologies.

GniruT

12:18 PM

hi

has anyone knowledge of complex numbers?

Alec Teal

Thanks @Boni for trying, I meant that.

user174558

You can turn off pings.

user174558

Also, if one is too scared of pings, one can just not enter the chatroom.

user174558

@SohamChowdhury and @Huy look cute.

Soham Chowdhury

well, that's a nice thing to know.

Huy

12:28 PM

I'm cuter

Alec Teal

.....pedo and a Justin Beiber fan. @Jasper thanks for the life advice!

Soham Chowdhury

Our man Mr. Huy has been busy these past couple of days.

user174558

@AlecTeal Bieber.

Alec Teal

Please #cut4beiber

GniruT

Can anybody help me with a question about complex numbers?

Soham Chowdhury

12:29 PM

Ah. Jasper scratches my itch these days.

sup, @Huy?

Alec Teal

@GniruT what does it say for the topic here?

GniruT

ups

Soham Chowdhury

just tell us. go on.

GniruT

how do you draw in Complex plane the imaginary part of "iz+1"

Soham Chowdhury

you don't. you draw the whole complex number in the plane. as a point.

Alec Teal

12:30 PM

Write z as a+bj and work out what iz+1 is

Soham Chowdhury

filthy engineer

$i > j$

(/s of course)

user174558

Too much strong language in this chat. First pedo, then filthy.

Alec Teal

the alphabet must be different in wherever you come from @SohamChowdhury because the natural ordering on letters gives $i<j$

user174558

I suspect the flags will come in soon.

Alec Teal

Also given we use i as the vector for the x axis.... j just makes sense for the complex part.

Huy

12:33 PM

correcting some geometry exercises from students

and then I have to attend a seminar on Regularity Structures

what u up to today @Soham?

user174558

Some places have no alphabet.

GniruT

@SohamChowdhury I have to draw the set ç

{iz+4:z of C, Im(z)>0}

user174558

I think people who have too much difficulty in elementary math should just drop the subject. It is not needed in daily life. We only need simple arithmetic to survive.

Boni

Eh. I couldn't do group theory for a long time.

Dr R Dizzle

Just dropping in to let you guys know that someone is flagging an awful lot of messages in this chat. I've been invalidating them because nothing offensive has came up, but you might want to watch out.

Alec Teal

12:40 PM

kk thanks

user174558

See what I said?

user174558

I know these flaggers.

Boni

This place is almost professional compared to Lounge<C++> over at StackOverflow.

Alec Teal

Maybe you're the flagger @Jasper

@Boni there are a lot of circlejerks on this site. It's not a very nice place.

Dr R Dizzle

@AlecTeal You can't flag your own messages.

Alec Teal

12:43 PM

@DrRDizzle I can't see what was flagged either. So that's inconclusive.

Doorknob

@AlecTeal putting aside the fact that his messages are being flagged, I don't think throwing around accusations is a very constructive thing to do

Alec Teal

@Doorknob clearly you've never played Cludo. Nor have I but I know the gist.

Doorknob

hah, "it was @AlecTeal in the chatroom with the keyboard!" :P

Alec Teal

@Boni I also hate the hot questions list, because some dumb-ass is like "why is a negative number times a negative number positive" and it becomes hot and gets so much attention but a good maths question, not accessible to the audiences OF THE OTHER SITES gets nothing.

Just skews rep further.

user174558

LOL, someone flagged me? LOL

user174558

12:45 PM

This is too much.

user174558

Also, better not use circlejerks and dumbass either @alec.

user174558

But I wonder who flagged me and for what.

Boni

@AlecTeal There were questions like that...? I am around mostly for the chat rather than the SE site itself. So I just meant that this chat itself is very mature in general.

Alec Teal

Yes @Boni - as a rule of thumb, the less accessible the topic the more mature it is. So here you can expect undergrads and above, as you know SE has a much broader set of users.

user174558

I am sick of these flaggers. They like to ban me from the chat.

user174558

12:51 PM

I did not flag anyone. If I want to flag, I will tell so openly.

GniruT

How to draw the set ${iz+4: z \epsilon C, Im(z)>0}$

Huy

mark one point belonging to that set. then mark the other points belonging to that set