Mathematics - 2014-03-03 (page 2 of 4)

11:03 AM

I'd have starred that if some of your assassins would back away.

Noone got the al pacino référence?

You may also watch this video

that is your third choice

Vrouvrou

@BalarkaSen have you found a good book on alg-topo ?

i will choose the second, thank you

I advise all others to watch the video

11:05 AM

@Vrouvrou No, and that's sad. Perhaps some professors would refer me one.

It's incredibly important for modern mathematics

@Mike Do you know how would I approach the problem on the second choice?

I refer you to the Katsamura-Dickenstein paper

@Mike it doesn't exist.

►

Eingalf

11:06 AM

Now I understand the whole nah business

Karl Kronenfeld

@Eingalf Ah, yes. We are transforming the star-board to a new and improved nah-board.

@PedroTamaroff I advise you watch "Bad First Date" by Mustache Wax Productions

I won't link it

Vrouvrou

i you found it just tell me ok ?

Eingalf

@PedroTamaroff hilarious

Hatcher is the canonical choice for perhaps the only canonical bit of homological algebra

@KarlKronenfeld I also advise you watch the mentioned video

11:09 AM

@Vrouvrou OK =) I'll ask my topo professors yesterday.

@Mike I've heard someone telling me that somedays ago. Was it you, Mike?

@Mike I don't get the connection to Inertia

@BalarkaSen nah

3

@skullpatrol Ponder on it

nah

Vrouvrou

@BalarkaSen you will ask him yesterday ??? you mean tomorrow ? right ?

@Vrouvrou yes. no pun in ten did

@skullpatrol You won't get any stars, skull pa troll

11:12 AM

>8(

22 mins ago, by skullpatrol

nah nah nah hey hey hey Goodbye

That's just 1 star.

Nothing compared to us

We surpass the Chat Guidelines star mark !

I never said that.

Okay, gotta go, byes.

@robjohn Are you there?

Hi @MattN.

@MattN. I am looking at your rep now

@mattn sup

685252

11:16 AM

@MattN. hi

@PedroTamaroff get on a computer soon, I have a great music video to show you

@robjohn Oh cool, thank you.

@PedroTamaroff Hi, nothing much. And yourself?

@685252 Hi.

@robjohn The rep itself is not all that important but I'm really curious as to how it mysteriously drops without any changes shown on my rep tab.

of course, it's also available to any who request it

the video?

yes

11:21 AM

:D

there's a sequel too

I'm still pondering "Inertia"

@MattN. Looking at a solution of FLT on Z[i]

@Mike @KarlKronenfeld

@PedroTamaroff Are you here yet

That star wall is so awful.

It's worse than Honey Boo Boo.

@Mike Where?

11:23 AM

on a computer

Yes.

watch

You should realize my answers are faster and better composed.

I know that song.

do you know the video

@Mike I give up, what is the connection?

11:25 AM

@MattN. Today's rep drop was because of the removal of this question.

@skullpatrol I don't know, I was hoping you'd figure it out for me.

Karl Kronenfeld

@PedroTamaroff You don't like translational symmetry?

@Mike SHIT. I am eating bro.

@KarlKronenfeld Not too crazy about it =D

You have a problem with reconstructive surgery?

@robjohn Oooh! I see! Now it makes sense. Deleted stuff doesn't show up as rep changes.

11:27 AM

@Mike Well when I am eating I do

:D

Thank you for investigating.

@robjohn "deleted by community" = automatically deleted by the site rather than by a mod?

I thikn it means 5 people voted to delete

I see.

@PedroTamaroff I am going to play some comedy skits in IZ

11:38 AM

@MattN. yesterday was because of the removal of this question and this question.

@robjohn Great, thank you. The mystery is now solved.

: )

@PedroTamaroff "We don't get much poor up here."

tty6

hello everebody.
please can you help me?

Seems unlikel

tty6

my question is about arithmetic coder.
can we take interval more than just (0,1]
for example (0,1024]

11:52 AM

@tty6 You can take any interval you want.

tty6

@PedroTamaroff thanks

usukidoll

ewwww Mike dat video r u nuts?!

anyway going to bed night

it's class as f

@Sawarnik yes?

$\Huge \text{Smoke on the water}$

12:33 PM

$\tiny\text{There's a fire in the sky.}$

:D

@DanielFischer What would be a decent way to show $n_2(A_5)=5$?

12:53 PM

Which of the following describes the best method of solving two-step equations?
A.
Apply the multiplication property of equality first, and then apply the addition property of equality to isolate the variable.
B.
Apply the addition property of equality first, and then apply the multiplication property of equality to isolate the variable.
C.
Apply only the multiplication property of equality to isolate the variable.
D.
Apply only the addition property of equality to isolate the variable.

Who thinks these kinds of questions up?

:-\

@skullpatrol What is multiplication property and addition property and all the other silly terms?

@PedroTamaroff You have $n_2(A_5) \geqslant 5$ by the five obvious embeddings of $A_4$ into $A_5$. Since $V_4$ is normal in $A_4$, you have $3 \mid [A_5 : N(P_2)]$, hence $n_2(A_5) \neq 15$.

@Sawarnik multiplying both sides of an equation by the same nonzero number...

@skullpatrol Why does that have to have a name?

@skullpatrol What, in the name of all that's holy, is a "two-step equation"?

1:06 PM

dunno

:(

Good point, Daniel.

I bet it's school, @skullpatrol, like hereabouts the schoolteachers (are required to?) say "ganzrationale Funktion" when they mean polynomial.

@robjohn This one I was talking about, math.stackexchange.com/questions/666099/when-is-arapd-arabcd

@skullpatrol Did you notice, you got 1 more star?

Oh, a propos stars: nah!

2

@Sawarnik thanks :D

@DanielFischer A "two-step equation" is an equation that needs two steps to solve. >8(

1:18 PM

@skullpatrol Are "steps" well-defined in that?

@DanielFischer addition/subtraction and multiplication/division

@DanielFischer But there can be no "best method of solving" !!!

So $3x+4 = 7$ is a two-step equation, I guess? For that one, I can see one way better than the other.

Yes. It depends on the equation.

Quite.

nah

2

1:27 PM

So now if we don't like someone's comment on the star board, we can bump it off using "nah" :-)

@skullpatrol Good point...and we would help each other in that.

yep

Even only two people could do it }:-)

starring each others "nah"s...

:} @skullpatrol What do you know about cricket?

It looks tough on the hands

never played though

?

1:32 PM

no gloves

like baseball

you have gloves for the keeper

behind the wicket

he's the only one, right?

apart from the batsman

yup

its not a big problem

have you played?

makes your hand rough and tough

Yup! Almost everyday!

1:35 PM

nice

looks like great exercise

I haven't played baseball nor understood how they make runs.

@Sawarnik The most popular sport in India, I think I have heard.

@DanielFischer Righto! Why don't you star my nah

@DanielFischer which says alot considering the population

@Sawarnik Sorry, missed it. Passed by too fast.

@skullpatrol Says a lot about the population. They have style.

1:39 PM

@skullpatrol Why don't you tell me about baseball

@Sawarnik They designed it after cricket.

I know tat.

what do you wanna know?

How do you make runs apart from the home run.

get on base before being tagged by the ball

1:42 PM

there are four bases?

@DanielFischer You know about cricket?

3 bases + home plate

You have to run a lot.

Hi friends. :-)

hi pal

@Sawarnik Not much. Haven't seen a match since the days of Ian Botham.

1:44 PM

I am looking for a finitely generated infinite group. Can anybody give me light?

@B.S. $\mathbb{Z}$?

@DanielFischer: Sorry I want it such that every elemnt is of finite order.

@DanielFischer: Some one hint me to consider Tarski monster group.

@DanielFischer: Do u think if this one is the only infinite group?

@B.S. I don't know that one, so it might or might not be.

@DanielFischer: Thank you Daniel for your time.

@B.S. No problem. Sorry I couldn't help.

1:53 PM

@DanielFischer

Tobias Kildetoft

@B.S. I doubt if the Tarski monsters are the only infinite finitely generated groups with all elements of finite order

@PedroTamaroff ?

Tobias Kildetoft

But I don't know any other examples

@TobiasKildetoft: Thanks for yout attempt. and the time. :)

Tobias Kildetoft

no problem

2:04 PM

Any hints for finding a holomorphic bijection between
$\{|z|<1\} \to \{ \text{Re } w >0\}$. This is an exercise of chapter about Möbius transformation and the Riemann Sphere.

@Kasper Well, Möbius transformation is a good hint already. Have you an idea how you might construct a Möbius transformation doing that?

@DanielFischer Was looking into a way to show $n_2(A_5)=5$.

I think one can easily show $\neq 1,3$.

By simplicity.

So it suffices it cannot be $15$.

And I guess one can do it by counting elements.

1 hour ago, by Daniel Fischer

@PedroTamaroff You have $n_2(A_5) \geqslant 5$ by the five obvious embeddings of $A_4$ into $A_5$. Since $V_4$ is normal in $A_4$, you have $3 \mid [A_5 : N(P_2)]$, hence $n_2(A_5) \neq 15$.

Ehm.. Well I know that Mobius transformations are combinations of translations/ inversions/dilatations and rotations.

@Kasper Already heard of the cross-ratio?

2:08 PM

But Re w > 0 is half of the complex plane. I just don't see how I can rotate or whatever into a circle.

@Kasper Inversion.

No, maybe it's called different in dutch, but it doesnt ring bells

@Kasper "Doppelverhältnis" for the Moffen, don't know the dutch word.

@DanielFischer Darn.

i google it

2:12 PM

@PedroTamaroff That should have been $3\nmid [A_5 : N(P_2)]$ of course. :(

Stupid tpyoes.

@DanielFischer What do you mean "...by the five obvious embeddings..."?

@PedroTamaroff Fixing $1$, fixing $2$, ...

Yes, I know that.

Greetings

2:14 PM

Oh.

Sorry.

Sorry. =D

Let $M$ be the set of natural numbers that do not contain cipher $9$ when writing
the numbers in base $10$. Test for convergence
$$\sum_{n\in M} \frac{1}{n}$$

@Chris'ssis That's a classic one, sire.

@PedroTamaroff It's a classical one, but it's nice.

If I'm not wrong, I think it was given to IMO.

This also reminds me of a very nice question I received many years ago from an American mathematician. He said: if you put all natural numbers in a single row, find a very easy way to identify the 1000.000.000th cipher in the row.

2:38 PM

@PedroTamaroff Maybe I can finish this essay in an hour.

Then I can nap for 3.

@Chris'ssis Easy would be Prelude> concatMap show [1 :: Int ..] !! 999999999. Not very fast, though ;)

@DanielFischer yeah, I see :-)

These days I did a bit of math combined with a bit of this ... :-)

Actually, this is what I'm learning right now.

2:58 PM

@Chris'ssis Herzliches Beileid.

@DanielFischer You mean "hearty condolences"? :-) "Beileid" might have more meanings I don't know yet.

Or "commiserations".

@DanielFischer Why commiserations? It seems fun to me to learn German. It's a really nice language.

We seem to have different tastes then. I don't find it particularly nice, it's rather clumsy IMO.

I need to know some German for the company where I want to go to. So, I try to learn some on my own. It's not easy, not hard, but I suppose it's just a matter of practice.

3:08 PM

I won't deny it can be useful to know German.

@Chris'ssis And if you have a question, feel invited to ask.

@DanielFischer OK. Thank you. :-)

I once wanted to know German for a book I was reading

I had a friend translate a stray line for me, and then regretted it upon hearing what it wasw

3:29 PM

@Mike What book was that?

@DanielFischer "Agape agape", by William Gaddis

that is not the same word repeated twice, I should note

One Greek, the other English?

Why would you need German for that book?

@DanielFischer Indeed

It's written in a stream-of-consciousness style, and occasionally the author's innermost thoughts are written down in his native tongue - unfortunately it turns out these are the thoughts one would not want a friend to translate, lest his friend things one is into some really weird books

(I recall that the sentence I asked for help on was incredibly Freudian)

I'm old-fashioned, I like the books I read to have structure, not stream-of-unconsciousness or noveau roman at all.

Gaddis is about as postmodern lit as it gets, so you'd definitely hate him.

He's also my favorite author of all time.

3:38 PM

Worse, @Mike, I ignore him ;)

That book is about a man who spent his life failing to write a book about the history of the player piano. So it's semi-autobiographical.

What is "the player piano"? A special kind of piano?

Piano that plays itself. They were all the rage in the 20s.

They were a shortlived fad.

Ah, these.