Mathematics - 2014-12-20 (page 7 of 8)

r9m

10:00 PM

@skullpatrol :P lol

user134177

@skullpatrol :P yes, i know ;)

Daniel Rust

maths makes everything better

Mathy Person

@MikeMiller Alright, thanks. I wasn't sure, so I thought I'd ask

Mike Miller

No worries

user134177

@DanielRust you are right

Jasper Loy

10:00 PM

@blondblau I am 33 and never had a girlfriend. So don't feel too bad.

Daniel Fischer

@MathyPerson No, that's $-1$, the one partition of $1$ has an odd number of parts.

Mike Miller

WHOOPS

Balarka Sen

@DanielRust Hello again.

Daniel Fischer

@MikeMiller It's correct modulo $2$.

Daniel Rust

@BalarkaSen hey

skullpatrol

10:01 PM

Hey @DanielRust leave my girl friend @blondblau alone

Mathy Person

lol @MikeMiller and @DanielFischer I see...I messed up the order to get 1 instead of -1. Thanks.

Daniel Rust

@skullpatrol but I don't wanna :(

Balarka Sen

nonsense. nonsense everywhere.

user134177

@JasperLoy ok, maybe it makes much things easier

Balarka Sen

nonsense nonsense everywhere, not a question to answer.

skullpatrol

10:02 PM

Do you like skulls @blondblau?

Huy

That's the best opening line I've ever heard, @skullpatrol.

skullpatrol

;D

user134177

@skullpatrol no :P

user134177

;)

skullpatrol

:(

Jasper Loy

10:04 PM

@blondblau But then again, I am not trying to trivialise your feelings. I know it can hurt a lot, so take your time to heal. It might be faster if you look for someone else.

Huy

LOL.

skullpatrol

I gotta try @blondblau

Daniel Rust

christ... you guys can get creepy

Balarka Sen

get used to it @DanielRust

and hey look you're addicted to the chat now

great

Huy

@DanielRust: Just join me and my popcorn and beer.

Mike Miller

10:05 PM

What are you drinking, @Huy?

Huy

@MikeMiller: Feldschlösschen, it's a Swiss brand.

Daniel Rust

@BalarkaSen I hang out in chat when I have free time. It doesn't happen often :P

Mike Miller

What kind?

evinda

@DanielFischer So, do you mean that it should be like that?


p=position-1;
l=j+1;
while (p>=0 and l<m and A[p]!=A[l]){
         if (A[p]<y*A[l]) l++;
         else p--;
}

@DanielFischer Or have I understood it wrong?

Huy

@MikeMiller: Is lager the correct English expression?

Mike Miller

10:07 PM

That's a type of beer in English, yeah.

Huy

Yeah, it's a lager.

Mike Miller

Great!

user134177

@Jasper Loy thank you

Daniel Fischer

@evinda You forgot to multiply with $y$ in the test of the while, but I guess that's a typo and not a misunderstanding.

skullpatrol

Are you a natural blond @blondblau?

Huy

10:08 PM

It's one of the most popular beers in Switzerland and by far my favourite. But only the bottled version, the one in cans I absolutely hate.

Balarka Sen

Me wants to know if I can Galois theorize over fibrations.

Huy

@MikeMiller: Do you like beer too, then?

Mike Miller

Absolutely.

Huy

@MikeMiller: Which kind of?

evinda

@DanielFischer Oh yes, right!!!
So should it be like that?


p=position-1;
l=j+1;
while (p>=0 and l<m and A[p]!=y*A[l]){
         if (A[p]<y*A[l]) l++;
         else p--;
}

user134177

10:09 PM

@skullpatrol yes, blond hairs, blue eyes

Daniel Fischer

@evinda Yup.

Mike Miller

Just about all of it. I guess I'd say I like tripels and pilsners the most.

user134177

in german "blue" meens blau

Mike Miller

But that's not fair to all the other beer I love.

r9m

@blondblau did you appear on the TV ?

evinda

10:09 PM

@blondblau Genau :D

Huy

@MikeMiller: Do you know San Miguel pilsner?

user134177

@evinda :)

user134177

@r9m ehm, no:P?

Mike Miller

I do, @Huy

Huy

@MikeMiller: How do you like it?

skullpatrol

10:10 PM

Good one @r9m ;D

Mike Miller

I don't dislike it, but I think it's pretty unremarkable. I think a good standard for pilsners is still Pilsner Urquell (the original!).

r9m

@skullpatrol nah ,, I got carried away a little too far :P

Huy

Ok. I don't know many pilsners, because I liked lagers so much so far and didn't want to ruin evenings. :P

I'll try the Urquell then when I see it.

Daniel Rust

did I miss the beer talk? I'm a big fan of ales

Huy

If I don't like it, I'll blame you.

Balarka Sen

10:11 PM

drunkards. drunkards all over.

Huy

@DanielRust: I only know the word ale in combination with ginger.

r9m

@BalarkaSen I don't drink !

Huy

@DanielRust: Is Guiness an ale?

Daniel Rust

@Huy yeah

Huy

Oh, then I like it, sometimes.

Daniel Rust

10:13 PM

In america they probably get called 'craft brews'

daOnlyBG

Guinness is a stout- and a pretty decent one, for not being a craft beer 8)

Huy

Only when having very unhealthy food in pubs.

user134177

@evinda are you from germany?

Huy

I don't America.

Balarka Sen

I know you amphetamine, @r9m. :P

skullpatrol

10:13 PM

Who comes into a math chat room 5 days before Christmas with that kind of news? @r9m

2

Huy

Lebst du denn in Deutschland, @blondblau?

r9m

@BalarkaSen :P LOL

user134177

@Huy ja, in Duisburg

Huy

@blondblau: Studierst du dort?

r9m

@skullpatrol Idk .. Santa ?

Daniel Fischer

10:14 PM

@r9m No, Santa drinks.

Balarka Sen

@r9m LEL

Ted Shifrin

heavily ...

user134177

@Huy ja, in Essen/Münster und du in Zürich, oder?

user134177

@Huy kennst du den Matheplanet?

Huy

@blondblau: Genau. Warst du schon mal in der Schweiz oder sogar Zürich?

@blondblau: Was meinst du damit? Ne Website?

r9m

10:15 PM

@DanielFischer how do you know ? :P

Mike Miller

Got my five; rep capped; done.

user134177

@Huy ja, das ist ein deutsches Matheforum. Zum Skifahren nur einmal

Ted Shifrin

Thank God, @Mike. You were becoming way too tiresome.

Balarka Sen

@blondblau and @Huy are discussing about blowing up New York city with nukes.

Mike Miller

Give me two hours to become tiresome agin, @TedShifrin

Balarka Sen

10:16 PM

Hey @Mike. I was targeting that.

Daniel Fischer

@r9m Experience. How else would my beers vanish?

Balarka Sen

You.

Mike Miller

Ah, I'd prefer you didn't discuss that, @Huy. I quite like that city.

user134177

maybe its better to talk in english

Ted Shifrin

You can always join Balarka on the ignore list, @Mike.

Balarka Sen

10:16 PM

I almost finished an answer.

Huy

@BalarkaSen: That reminds me of the top answer to the urban legends on MO, did you read that?

r9m

@DanielFischer :P

user134177

but my english is bad, but i will try it

Huy

@blondblau: Ich kenne nur matheboard.de. Aber das mag ich nicht sehr.

Balarka Sen

@TedShifrin Why?

Why me?

user134177

10:17 PM

@Huy ich glaube, matheplanet ist die größte deutschsprachige community

Mathy Person

@PedroTamaroff I am currently working on a problem that involves: let $P^*(x)=\sum_{n=0}^{\infty} p^*_nx^n$, where $p^*_n = \binom{\text{number of partitions of }n}{\text{into an even number of parts}} - \binom{\text{number of partitions of }n}{\text{into an odd number of parts}}$. Would it be better to fully expand it out (I got $1-x-x^3+x^4+x^5+x^6-x^7......$ so far), or is there an easier way like the problem you helped me with earlier?

user134177

das größte deutsche matheforum *

user134177

wollte ich ich schreiben, matheboard mag ich auch nicht

Jasper Loy

@TedShifrin It makes it harder to follow the chat conversation if you ignore someone. You might even misunderstand what is being said.

Ted Shifrin

I do that regardless, @Jasper.

Balarka Sen

10:19 PM

:(

skullpatrol

The best way to improve your English is to practice here @blondblau

Mike Miller

@Ted Well, I was barreling towards the ignore list anyway.

Balarka Sen

Why ignoring me, @Mike?

I did nothing!

Ted Shifrin

Speaking of ignore, @Mike, have you seen Jacob recently? I messaged him and he hasn't replied.

I hope he's doing ok.

evinda

@DanielFischer And now if A[p]!=A[l] we need to do an other traversal?

Mike Miller

10:21 PM

@DanielRust If I'm around, you haven't missed beer talk.

Balarka Sen

oh ok

Mike Miller

I saw him the week before finals, @Ted. I'd prefer not to talk about non-chat-denizens here; I'm glad to talk elsewhere.

Jasper Loy

@MikeMiller You can talk in my bedroom.

Ted Shifrin

Quite appropriately. You know where elsewhere to find me.

Daniel Fischer

@evinda Yes, if we haven't found anything, we must look further. Now we multiply the negative number with $y$. Take care of the sense of the inequalities.

Ted Shifrin

10:23 PM

smacks @Jasper

daOnlyBG

hey guys, this is an incredibly basic question- I'd like to show that the modulus of a complex variable $z$ is $|z|=\sqrt{x^2+y^2}$

Jasper Loy

I am actually talking to Ramanujan now over email. Ethan, to be precise.

daOnlyBG

so if I let $z=x+yi$

Daniel Fischer

@daOnlyBG Usually, that's the definition.

Ted Shifrin

@Jasper: We have uncountably many Ramanujan-wannabes here.

Daniel Rust

10:24 PM

@daOnlyBG that's the definition of the modulus

daOnlyBG

ok, but why is it defined as such?

Huy

@DanielFischer: Don't you define it as the distance from the origin and then it follows from Pythagoras?

daOnlyBG

$z^2=x^2-y^2-2xyi$

Balarka Sen

One of them is Chris'ssis, @Ted

skullpatrol

The one.

Daniel Fischer

10:24 PM

@daOnlyBG You need $z\cdot\overline{z}$

Ted Shifrin

but $z\bar z = x^2+y^2$, @daOnly

Daniel Rust

@daOnlyBG It's the distance in the complex plane that $z$ is from zero

Jasper Loy

@TedShifrin Aha. I give that label to Ethan and Chris's Sis only so far.

daOnlyBG

ok, so the modulus is $|z|=\sqrt{z*z\bar}$?

Ted Shifrin

Well, it is true that $|z^2| = |z|^2$, so go for it, @daOnly :)

evinda

10:26 PM

@DanielFischer Should we do it like that?
 if (A[p]!=y*A[l]){
             while ((p>=0)&&(l<m)&&(A[l]!=y*A[p])){
                   if (A[l]<y*A[p]) p--;
                   else l++;
             }
         }

daOnlyBG

i'll just take it for granted then- I'd like to know why it's defined accordingly;

I don't see how that's the distance from z to the origin

Daniel Rust

@daOnlyBG draw a triangle and drop a hypotenuse

Ted Shifrin

damn, @DanielF, you're acting geometric :D

All teasing aside, @daOnly, it is the distance formula plain and simple.

daOnlyBG

alright, I guess

I got it

Daniel Rust

draw a picture :P

Daniel Fischer

10:29 PM

@evinda You should be able to check such things yourself, read your code carefully, and see what it does. (And you should find a couple of mistakes. Not many, though.)

daOnlyBG

I drew a pic, just not sure I understand where the conjugate fits in

Alizter

cough cough

Chris's sis

@r9m I have something amazing. I cannot say I saw many proofs, but I'm sure you might be able to say if there is something similar out. :-) I was working on something completely different when I saw this possible connection.

Balarka Sen

throws antiallergics down @Alizter's throat

Daniel Rust

@daOnlyBG can you at least see why $\sqrt{x^2+y^2}$ is the distance from $z$ to the origin?

daOnlyBG

10:31 PM

yeah, I can

Daniel Rust

@daOnlyBG using Pythagoras' theorem

Ted Shifrin

Because, by the geometry of complex multiplication, when you multiply two complex numbers, their moduli multiply and their angles add. So multiplying $z$ and $\bar z$ gives you a positive real number of length $|z||\bar z| = |z|^2$.

Alizter

@BalarkaSen I have a cold dammit

Ted Shifrin

@Alizter: Take a break from math and physics and get healthy. It's your bedtime.

Don Larynx

Anyone else find it interesting that the digital roots of triangle numbers follow the pattern $k_n = 1, 3, 6, 1, 6, 3, 1, 9, 9 : n = 1, 2, \dots$ for $k = r mod 9 : r \in \sum_{k=1}^n x, \dots$?

Balarka Sen

10:31 PM

It's my bed time too!

daOnlyBG

okay, got it- thanks, sorry if it's very trivial

skullpatrol

Later

Daniel Rust

@daOnlyBG $z\bar{z}=(x+iy)(x-iy)=x^2-ixy+ixy+y^2=x^2+y^2=|z|^2$

Ted Shifrin

$^2$ @DanielF

Danke.

Daniel Rust

@TedShifrin what's with the F? :P

Ted Shifrin

10:33 PM

Because you whined about my pinging you all the time, @DanielR.

Balarka Sen

@Daniel pings both you and @DanielFischer

Daniel Fischer

@DanielRust Habit. I'm much more often here in chat than you recently.

Daniel Rust

@TedShifrin haha true

Mike Miller

@TedShifrin FYI - there's actually another DanielR who gets pinged :)

Ted Shifrin

I think we had another Ted recently. Very confounding.

Daniel Rust

10:34 PM

Yeah, I get his pings sometimes

Balarka Sen

heh

Ted Shifrin

Yes, but I can only do so much .... @Mike @DanielRust

Chris's sis

@r9m at any rate, I didn't see anything similar so far, but that doesn't mean such a way (or a similar way) doesn't exist. I just wanna be cautios.

Balarka Sen

every subgroup of the generalized quaternion group contains $\langle 1, x^n \rangle$, right?

skullpatrol

@DanielFischer I have never seen so many people speak German in this room at one time when @blondblau said she has blond hair and blue eyes :D

Chris's sis

10:36 PM

@r9m The good part is that the proof can be easily taught in high school and uni. I mean it's hard not to understand it, it's less probable. This is only possible when missing the most basic knowledge.

Mike Miller

We had a Teddy, @Ted, but they're not in chat anymore (I say they're in chat if @Ted autocompletes to more than one name... if it does, everyone it could autocomplete to gets pinged)

Daniel Fischer

@skullpatrol Gentlemen prefer brunettes.

Ted Shifrin

yes, I know the autocomplete game ...

@Chris'ssis: This truly is getting tiresome. Either share the proof or quit it. Your secret bragging is just too much.

9

skullpatrol

Apparently @DanielFischer

Chris's sis

@TedShifrin I don't understand your point. I'm discussing with @r9m, and it's no bragging. @r9m knows that when I say something is the way I say it.

Ted Shifrin

10:38 PM

It is relentless bragging. And it's been going on all day.

It may be justified, but it may not.

Pedro Tamaroff

@TedShifrin Just use the ignore button, eh?

skullpatrol

^

user134177

i'm sorry, i wirte in english here next time

Balarka Sen

I think we should ignore, yeah.

user134177

*will write

Chris's sis

10:39 PM

@TedShifrin I mean you should ignore me. I agree with you. God helps you find the ignore option.

skullpatrol

Thanks @blondblau ;D

Pedro Tamaroff

@BalarkaSen What about the trivial subgroup?

Ted Shifrin

@blondblau: Es gibt Leute hier die deutsch sprechen :)

Balarka Sen

@PedroTamaroff Except that.

Khallil Benyattou

Teach me some German next time, @blondblau! ^_^

Chris's sis

10:40 PM

@TedShifrin do you think that I'm bragging in front of you? I have very very huge, amazing dreams that have no coonection with bragging with such a proof in front of you.

Ted Shifrin

God doesn't help me do anything.

Jasper Loy

@TedShifrin I think @Chris'ssis just likes to repeat stuff just like I do too.

Khallil Benyattou

In other news, VLC is getting all Christmassy!

Jasper Loy

@Chris'ssis Are you going to email me like you said just now?

Ted Shifrin

Ordinarily, math people have the urge to share their discoveries, not to hide them, @Jasper.

Khallil Benyattou

10:41 PM

Jasper Loy

@TedShifrin Aha, but we are no ordinary mathematicians in this chat. We are a bunch of loonies.

Chris's sis

@TedShifrin Sorry if you misunderstand me. I appreciate you as a professor, maybe I'm that kind of person hard to understand.

Ted Shifrin

Speak for yourself, @Jasper :D

Alizter

@TedShifrin Does Newtonian mechanics still work in higher dimensions?

Balarka Sen

Ordinarily, expert mathematicians also tend to be humble.

skullpatrol

10:42 PM

Welcome to the loonie bin @blondblau

Ted Shifrin

Sure, @Alizter. That's where symplectic manifolds come from :P

Chris's sis

@BalarkaSen No, I don't wanna humble at all, but when you go the church maybe.

Alizter

@TedShifrin Good.

Jasper Loy

@BalarkaSen I don't think @Chris'ssis is arrogant. She is just marvelling at the beauty of her result, she is not arrogant.

4

Ted Shifrin

But Newtonian mechanics, as you know, has its limitations. :)

Alizter

10:43 PM

@TedShifrin Go on?

I don't know

Chris's sis

@JasperLoy Exactly!!!

Alizter

or I am unaware that I don't or do know

Ted Shifrin

Relativity theory ... first special, then general, then quantum mechanics ...

user134177

@TedShifrin cool:) is german your mother lenguage? @KhallilBenyattou i can do it ^^

user134177

@skullpatrol :)

Alizter

10:44 PM

@TedShifrin oh

Ted Shifrin

Nein, @blondblau. Ich hab' deutsch (und französisch und ein bißchen russisch) studiert.

Alizter

Real world limitations?

Huy

@TedShifrin: Is that an order you would study the topics in?

Balarka Sen

I disagree, @Jasper. I find her extremely arrogant and she finds everyone to be jealous at her.

I mean seriously, what the hell.

Alizter

I like to sit in my mathematical wonderland

Ted Shifrin

10:44 PM

definitely not, @Huy, but I'm no physics expert at all.

Jasper Loy

@BalarkaSen Well, I think only I understand her well enough...

Huy

@TedShifrin: What kind of order is it then? because of the "then"s, I ask

Ted Shifrin

special relativity, then quantum ... general takes a ton of graduate differential geometry :P

my then's were neither true to history nor true to learning, @Huy. I apologize.

Huy

I never specifically studied SR. I'm worried I will have trouble studying GR. :s

Ted Shifrin

SR is very cool, @Huy. You replace the orthogonal group with the Lorentz group :)

The twin paradox is one of my favorites from college.

skullpatrol

10:47 PM

Do you know why he chose the name "special" @Huy?

Huy

@TedShifrin: I never specifically studied it, but it came up during our Physics 1, 2 and 3 courses. Also during our course about General Mechanics.

Balarka Sen

Huh. I guess I'll have to try the next sunday.

Mike Miller

@Ted Is mechanics the entire origin of the idea of symplectic manifolds?

Ted Shifrin

I believe so, @Mike, but I'm no history expert. But I'd bet money on it :P

r9m

@Chris'ssis So you do think I am a grave digger ? -_- (referring to 'I just wanna be cautious') ...

Huy

10:48 PM

@skullpatrol: Because it only deals with inertial frames, iirc?

r9m

@Chris'ssis I like less probable proofs a lot :D

Mike Miller

"The unreasonable effectiveness of physics in mathematics"...

user134177

@TedShifrin cool:)

skullpatrol

Do you gamble @TedShifrin?

Ted Shifrin

classical, @Huy?

Balarka Sen

10:48 PM

Galois covers @Mike

Ted Shifrin

oh, and special relativity, too, I guess :)

no, @skull. One of my colleagues and I make nickel bets :P I am not a good poker player :D

Mike Miller

Shoulda asked when I was on my computer, @Balarka

The Eagles game is on!

Chris's sis

@r9m Actually, I'd ask you nicely to dig as deep as you can. I'm very curious about that. I need to find a way to send you my proof (but not know - as happened with other proofs) :-)

Balarka Sen

oh noes

Huy

@TedShifrin: We covered Newtonian mechanics, two-body systems, three-body systems, oscillating problems, Lagrange formalism, Hamiltonian systems, Hamilton-Jacobi, rigid bodies, and SR

@TedShifrin: It was a course titled "General mechanics"

Ted Shifrin

10:50 PM

Lovely course, @Huy

You should know the right way to approach the physics problems I was going to pose to @Khallil and @Alizter. :) But I'm only halfway through posing.

r9m

@Chris'ssis yay !! So you wanna cut the deal for the shinigami eyes human ? ;) (evil grin) good ;)

Balarka Sen

Well physics sucks.

Chris's sis

@r9m What on earth that mean? :-)

Mike Miller

Ah, looks like you broke that promise you made a while back, @Balarka

Khallil Benyattou

It's a Death Note reference, @Chris'ssis.

Huy

10:51 PM

@TedShifrin: Is there a US equivalent for that course? Classical mechanics?

Alizter

@TedShifrin Is it not draw diagram, work out values, equations then rearrange and plug

Balarka Sen

I thought I was making promises about branches of mathematics, @MikeMiller?

Chris's sis

@KhallilBenyattou Ahhhhhhh :-)

Khallil Benyattou

I wouldn't cut the deal, @r9m. I'd get Misa to do it for me. =P

r9m

@KhallilBenyattou Bingo !!

skullpatrol

10:51 PM

Stop saying that physics sucks @BalarkaSen

Balarka Sen

Shhhh @skull

Hell.

Well, he is not gonna unignore me anyway. So...

Ted Shifrin

We tend not to do relativity in our upper-division mechanics courses, so far as I know, @Huy. We don't at Georgia, and MIT didn't, either.

That, now, @skull?

Huy

@TedShifrin: because it is too simple or hard or because it differs from the rest too much?

r9m

@KhallilBenyattou perhaps she has to find a guy who could be his Misa ;) (unless there's a Light Yagami pulling the strings and she is Misa) Either way I am a Shinigami ! (I win either way :P)

Balarka Sen

And in any case @Mike. My promise was that if he unignores, I'll stop being an ignorant prat.

skullpatrol

10:54 PM

It is a matter of principle @BalarkaSen

Mike Miller

You run the risk of having everyone else ignore you too

Ted Shifrin

I dunno, @Huy. I can ask my physics professor friends. We do relativity in a separate "Modern Physics" course.

Balarka Sen

@MikeMiller What, physics?

just for physics?

Huy

ic. it is interesting to see how universities seem to structure courses in such different ways

Balarka Sen

i mean, c'mon.

Khallil Benyattou

10:55 PM

There's an L somewhere, @r9m. Since that's the case, you lose both ways! =P (L is the best.)

Ted Shifrin

Sure, @Huy, I have plenty of gripes about the "standard" undergraduate math curriculum most places :P

Huy

@TedShifrin: For example?

Balarka Sen

I'm even prepared to study diff geo if he unginores me @Mike

otherwise, nah.

Ted Shifrin

I tend to think algebra is taught too much by symbol-pushing. Most students never see linear algebra integrated with multivariable calculus/analysis. I am a firm believer in concrete examples and computations, even in theoretical courses ...

r9m

@KhallilBenyattou But anyway .. Ryuk had the last bite !

Huy

10:59 PM

@TedShifrin: I'm not sure what you mean. Could you be a bit more concrete, with this example?

Ted Shifrin

Huh? @Huy mean about what?

Transcript for

$Mathematics$ Mathematics