Mathematics - 2019-02-08 (page 3 of 4)

anakhro

22:01

Hmmm. Yeah. The flowbox with ODEs is nice though because it is one "dimension". Would it be not a bad idea to explain it that we need it "in multiple dimensions" and the involutivity allows us to do that?

Riccardo

@TedShifrin No I don't know him :(

Leaky Nun

@TedShifrin do you do ODEs on manifolds?

anakhro

Again, I'd come up to the spot where the involutivity being the missing piece of the puzzle seems a little mysterious.

Other than observing that when you try this with examples, involutivity seems to be the missing ingredient in all the counterexamples...

Ted Shifrin

@Leaky: You mean me personally? Some of my papers have involved this in some way.

Leaky Nun

do you have interesting examples?

Ted Shifrin

22:03

@anakhro: It's like discovering that you need a form to be closed in order for it to be exact. It really is a generalization of that.

"Interesting" is very much in the eye of the beholder. You and I have antipodal taste in mathematics.

Leaky Nun

$y'' = k^2 y$ on $S^1$?

Ted Shifrin

No, not that sort of thing.

My interest comes from geometric phenomena.

Leaky Nun

I don't understand

Ted Shifrin

Things like you wrote down don't even make sense on manifolds. What does $'$ mean?

Leaky Nun

good point

Ted Shifrin

22:06

I'm talking about things like asymptotic curves on surfaces (and generalizations to projective geometry).

anakhro

@LeakyNun every (smooth) vector field on a manifold gives rise to an ODE.

CaptainAmerica16

cool

Leaky Nun

interesting

anakhro

It's your basic classical mechanics. You integrate the vector field to integral curves: curves that are everywhere tangent to the vector field.

Ted Shifrin

hi @CaptainAmerica

CaptainAmerica16

22:08

Good evening

Ted Shifrin

looks at clock and sees it's only 2:10 PM

CaptainAmerica16

oof, sorry. I forgot i'm 3 hours ahead

Ted Shifrin

@anakhro: Hope you'll find some stuff of interest in all the pages I sent you.

Leaky Nun

it's obviously 10:10 PM

anakhro

@TedShifrin I hope I will, too! I usually learn at least a few things whenever I read something new, so I am sure I will be thanking you for something in there in the future!

CaptainAmerica16

22:11

@LeakyNun Obviously

Mike Miller

I'm told to use SabbaticalHomes.com to find a place to stay for a quarter.

Seems like it's not a terrible choice.

CaptainAmerica16

What anakhro said makes me think about how there's an equation for all the graphs in calc class

Jacksoja

I think black republican are practical

Mike Miller

@TedShifrin The general case (instead of just a 2 x 2 block matrix)?

@LeakyNun I know. I could have found a reference but decided you would find it if you cared. :)

Leaky Nun

great

Ted Shifrin

22:12

@MikeM: $n\times n$ case in a $(2n)\times (2n)$ matrix.

Mike Miller

yup

@Riccardo I agree. I don't know Tim, but he seems to be a good advisor.

Also, I like his work.

Jacksoja

@TedShifrin @LeakyNun Hi brothers

Ted Shifrin

hi @Jacksoja

Mike Miller

@TedShifrin Aha, that's what I was thinking. Leaky wanted 2 x 2s in a 2n x 2n.

Ted Shifrin

I have no idea what that remark up there meant, @Jacksoja.

Leaky Nun

22:13

@Jacksoja "brother"?

anakhro

@CaptainAmerica16 at least locally.

Mike Miller

I've only seen a computational proof of the m x m inside km x km case.

Ted Shifrin

Oh, @MikeM, for that I would think exterior algebra, I think.

Mike Miller

Maybe @LeakyNun can work out a proof for us.

Ted Shifrin

But I would need to think about it.

Jacksoja

22:14

@LeakyNun does everything offend you lately ?

Leaky Nun

when did I say i'm offended

Jacksoja

@TedShifrin youtube.com/watch?v=Bgyt4Jdk9TQ

Ted Shifrin

Well, @Jacksoja, I asked you the same question a few days ago.

Jacksoja

@TedShifrin I was watching a sketch on Youtube , funny stuff

Ted Shifrin

That link doesn't work in the US, @Jacksoja.

Jacksoja

22:14

oh really why ?

Ted Shifrin

I have no idea.

@MikeM: Do you understand this?

Leaky Nun

@Jacksoja maybe because of the title?

Ted Shifrin

No, YouTube often will have things that work in one country but not in another.

Leaky Nun

I know, I'm saying that the title might be a bit sensitive in the US

(I clicked on the video)

CaptainAmerica16

@anakhro Interesting, hope I get to learn stuff about ODE's within the next year or so.

Jacksoja

22:16

then maybe type " key and peele " black republicans

CaptainAmerica16

It's Key and Peele, they have all kinds of videos like that available here

Mike Miller

I would need to think and I am not so interested in thinking.

Jacksoja

they make funny sketches

Ted Shifrin

LOL, thanks, Mike.

Mike Miller

I'm trying to make sure I'm not homeless in April...

CaptainAmerica16

22:17

@Jacksoja I rewatch their stuff all the time. It's hilarious XD

Ted Shifrin

April? I wondered what you were talking about.

Jacksoja

@CaptainAmerica16 Ikr :D

CaptainAmerica16

@Jacksoja You have any favorites?

Leaky Nun

@Ted I don't really know what OP wants

(regarding this question)

Ted Shifrin

I think his question is natural enough. He wants something that will tell him about the Plücker embedding of Grassmannians. That's why he wants decomposables to map to decomposables.

Jacksoja

22:21

@CaptainAmerica16 concequences and that french talking scene wbu ?

CaptainAmerica16

@Jacksoja Definitely consequences, but also every meegan scene and the one where the rapper makes the confession.

I don't remember the name of that one

Mike Miller

@TedShifrin my roommate graduates in march

Leaky Nun

@TedShifrin but he also realized that the naive embedding won't work

Paul Plummer

I recently started to get into skateboarding again, youtube recommends a video "riddles in mathematics", which ends up being a skateboard part

Leaky Nun

and also someone in the comment pointed out that the other thing is a quotient of this thing

and sections don't feel very right to me

Jacksoja

22:23

@CaptainAmerica16 haha , yeah in those scenes i forget that peele is a man lol

Paul Plummer

Google knows too much

CaptainAmerica16

@PaulPlummer Hey I skate. I'm not very good though

@Jacksoja Ikr, lol

Ted Shifrin

I haven't thought about it, @Leaky, but it seemed like something that might be down your avenue.

ÍgjøgnumMeg

Hi all

Alessandro Codenotti

Hi @Paul

Paul Plummer

22:24

@CaptainAmerica16 I am terrible. I actually stopped because I injured myself learning to ollie over things over a year ago

Mike Miller

@PaulPlummer What a life

CaptainAmerica16

@PaulPlummer I tried to ride down a ramp at the skate park and hit my mouth on the ground. It was really bloody.

Ted Shifrin

hi @ÍgjøgnumMeg

ÍgjøgnumMeg

Hey @Ted :)

Jacksoja

@ÍgjøgnumMeg Hi brother

ÍgjøgnumMeg

22:24

Hey @Jacksoja

Paul Plummer

@AlessandroCodenotti Hi

Jacksoja

I like how your name shows up the first when I try to text some

ÍgjøgnumMeg

Heh heh

Jacksoja

What is that letter I with a dash on it ?

ÍgjøgnumMeg

It's pronounced like "uj"

Alessandro Codenotti

22:25

Capital accented i?

ÍgjøgnumMeg

Í

Ted Shifrin

@Alessandro wants italic I's.

ÍgjøgnumMeg

Í

Alessandro Codenotti

Érico also shows up as second suggestion because of the accent

Ted Shifrin

LOL

ÍgjøgnumMeg

22:26

Ý

lol

Jacksoja

Ü

Alessandro Codenotti

I'm almost sure we only have ì in Italian, not í

ÍgjøgnumMeg

Does it shift emphasis?

Jacksoja

I think he is joking , there is no such letter in italian

Alessandro Codenotti

Yeah, emphasis is on the vowel with an accent

Paul Plummer

22:28

@CaptainAmerica16 I wonder how much blood has been spilt in that skatepark(over all people)

ÍgjøgnumMeg

I see, same in Spanish

CaptainAmerica16

@PaulPlummer lol

Jacksoja

É

Paul Plummer

Sorry Ted

Alessandro Codenotti

Like "papà" (dad) and "papa" (pope), the former has emphasis on the last vowel, the latter on the first

Jacksoja

22:29

@ÍgjøgnumMeg How many languages do you know ?

ÍgjøgnumMeg

That's cool

Alessandro Codenotti

But it's kinda weird, we only use accents on vowels at the end of a word in Italian

Ted Shifrin

Why sorry Ted @Paul?

CaptainAmerica16

@PaulPlummer I try to minimize the damage by wearing a helmet and pads, but I always get funny looks.

ÍgjøgnumMeg

@Jacksoja I speak 3 fluently, a couple more "okay-ish"

Jacksoja

22:30

@ÍgjøgnumMeg which are ?

Paul Plummer

Oh I accidentally sent Caps message to you, but I changed it back @TedShifrin

ÍgjøgnumMeg

English, German, Swedish

Alessandro Codenotti

Like "baratro" is read as "baràtro", but normally the emphasis would be on the first vowel so you need to know that since it's not written. It doesn't make much sense

ÍgjøgnumMeg

lol weird

Jacksoja

That is very impressive

ÍgjøgnumMeg

22:31

@Alessandro Swedish and Norwegian have some tonality in them that changes meaning in the spoken language

Ted Shifrin

Oh, I guess I missed it totally; sorry, @Paul.

Paul Plummer

Your new profile image is messing me up @AlessandroCodenotti

cool though

Alessandro Codenotti

You'll get used to it, so far it's a small data set but I change it every 5 years on average

ÍgjøgnumMeg

like bønner means "seeds" and bønder means "farmers", they are pronounced exactly the same except from the tones

Alessandro Codenotti

Oh, that's weird

Leaky Nun

22:33

@ÍgjøgnumMeg looks like Danish

Alessandro Codenotti

(I only changed it once yesterday since I joined MSE 4 years and 10 months ago :P)

ÍgjøgnumMeg

@Leaky Bokmål basically is Danish

lol

Ted Shifrin

I've kept my surface picture for most of my stay here.

Leaky Nun

lol

why would you learn bokmal

ÍgjøgnumMeg

It's the written standard with the most resources and is the most widely spoken in Norway

"spoken"

I mean, the most standardised Norwegian

Alessandro Codenotti

22:34

The image I'm using now is the cover of an album

CaptainAmerica16

which album?

Alessandro Codenotti

Departure Songs, by We Lost the Sea

Leaky Nun

@ÍgjøgnumMeg how did you learn Swedish?

ÍgjøgnumMeg

@Leaky I had a girlfriend from Sweden lol

this is how I learn languages

CaptainAmerica16

@AlessandroCodenotti Oh, sounds interesting. Gonna have to check Spotify for that later

Leaky Nun

22:36

@ÍgjøgnumMeg how long have you learnt it before you became fluent?

MatheinBoulomenos

somtimes accents could be useful in German. Depending on the pronouncation, "umfahren" can mean "drive over" or "drive around"

ÍgjøgnumMeg

@Leaky only took like a year to speak reasonably well

Leaky Nun

interesting

Alessandro Codenotti

It's a sad instrumental album where every song is inspired by an epic but failed human feat

CaptainAmerica16

@AlessandroCodenotti Perfect, I love instrumentals. And I've been on a hunt for sad-sounding music since Monday.

ÍgjøgnumMeg

22:37

you can often guess words if you already know German

lol

Alessandro Codenotti

@ÍgjøgnumMeg lol that's basically how I first decided I wanted to study in Germany and learn German

ÍgjøgnumMeg

A laaady?

Alessandro Codenotti

Yep

ÍgjøgnumMeg

Nise

:)

Jacksoja

@ÍgjøgnumMeg but what is your mother tongue language?

english or german ?

Alessandro Codenotti

22:39

That was quite a few years ago, but I guess this idea of studying in Germany remained

ÍgjøgnumMeg

@Jacksoja English :P

@Alessandro fair hahah

Jacksoja

@ÍgjøgnumMeg okay, for someone born speaking English , it is even more impressive that you know other languages haha

ÍgjøgnumMeg

Yeah there's a lot of lazy English people

:P

Ted Shifrin

@Jacksoja: I resemble that remark. I've studied Latin, French, German, and Russian.

CaptainAmerica16

dang

Ted Shifrin

22:40

My French was once as good as my English, and my German was decent.

CaptainAmerica16

I dropped Spanish in my second year

Leaky Nun

I don't really understand how someone can learn a language by listening to radio, like how would you know what the words mean

Jacksoja

My point is , most don't bother because English is used all over

Leaky Nun

or living in a place for some time

Ted Shifrin

Most Americans have a horrible attitude about languages and cultures, admittedly.

CaptainAmerica16

22:41

I'm pretty good with sign language though. ASL particularly.

Jacksoja

But Ted you still know french

ÍgjøgnumMeg

oui

Jacksoja

I have seen you talking on this chat just the other day with someone in french

Ted Shifrin

Oh, we had a whole Parisian contingent in here for a few years, so I did lots of French. There are still a few others that I don't know as well.

Mike Miller

@TedShifrin Yeah, I can't stand when people talk in C++ near me.

Ted Shifrin

22:42

well, @MikeM, you do hang around more of the computer crowd than I do.

Mike Miller

I kid.

Jacksoja

Ted is a very patient guy , I would flipp out if someone told me that.

CaptainAmerica16

@MikeMiller Oh, i was about to ask you if you have any favorite languages.

Ted Shifrin

@MikeM: Has the bleating started?

Mike Miller

Who's bleating?

@CaptainAmerica16 I haven't really coded in at least 5 years. I'll learn to again before I die. Who knows when.

Ted Shifrin

22:44

you are, apparently. You kid.

Mike Miller

bans Ted

Ted Shifrin

Yippee!!

Alessandro Codenotti

@MikeMiller when fortran2030 comes out, obviously

CaptainAmerica16

@MikeMiller I haven't had a chance to code much for fun recently. I'm trying to learn C#.

I don't get the bleating comment. According to google, it means complaining

MatheinBoulomenos

magma is great. If only it wasn't propriertary

Mike Miller

22:45

The sound goats make is called bleating.

A kid is a young goat.

@CaptainAmerica16 I hear you should learn Python as a first language.

CaptainAmerica16

Wow. That went right over my head.

Alessandro Codenotti

I might have to learn Haskell for a project I'd like to do next semester but I don't know yet if I'll be able to (they only take 6 people)

Leaky Nun

@MatheinBoulomenos well but I want my binary operation to be associative

MatheinBoulomenos

@LeakyNun no the language

CaptainAmerica16

@MikeMiller I know a few other languages. I wish I had started with Python. I started with java, it was a rough start.

Leaky Nun

22:46

r/whoosh

Mike Miller

A proprietary magma is a set with a binary operation, but the operation is a secret

Leaky Nun

@MikeMiller no he means the language cannot be downloaded free of charge

MatheinBoulomenos

it's worse, you can't even buy it as an individual

Mike Miller

is this a meta r/whoosh?

Leaky Nun

yes

Mike Miller

22:48

phew

i almost got got there

Leaky Nun

lol

Kasmir Khaan

@LeakyNun am gonna go straight at it, do you want to my best man on the wedding ?

CaptainAmerica16

@KasmirKhaan Mazel Tov.

Kasmir Khaan

never mind ! how about you Ted ? @TedShifrin

@CaptainAmerica16 captain america? :D

Jacksoja

@KasmirKhaan sign me in

Ted Shifrin

22:51

@Kasmir: How about what?

CaptainAmerica16

idk :P

Jacksoja

I was first

CaptainAmerica16

He asked me before you. I implicitly agreed - to whatever this is.

Kasmir Khaan

@TedShifrin being best man at my wedding lol

Ted Shifrin

Oh, is there a wedding?

Kasmir Khaan

22:52

haha nah just horsing around

how are you yall ?

CaptainAmerica16

Will there be food

dang it

Ted Shifrin

I have quit going to weddings, anyhow, unless they're gay weddings ...

CaptainAmerica16

I went to a wedding this summer

past summer

Kasmir Khaan

what do you mean ?

CaptainAmerica16

I did math most of the time and left hungry.

Ted Shifrin

22:53

LOL, @CaptainAmerica.

Kasmir Khaan

who does that Cap merica?

CaptainAmerica16

@KasmirKhaan Does what?

Kasmir Khaan

when you are in a wedding you should dance and eat ._. or eat and dance

not doing something else

CaptainAmerica16

I try to avoid dancing in public.

Kasmir Khaan

haha i try to avoid dancing in genera

CaptainAmerica16

22:55

I did eat. But they always give side eyes if you try to go back for thirds.

Kasmir Khaan

dont like it and very bad at it

ÍgjøgnumMeg

instagram.com/p/BicvcRTAD-i

Kasmir Khaan

wow

ÍgjøgnumMeg

Here's a good video of me dancing

Kasmir Khaan

you going for thirds?

Ted Shifrin

22:56

@ÍgjøgnumMeg: Yup, drunk.

CaptainAmerica16

@KasmirKhaan ;-; no one understands

ÍgjøgnumMeg

@Ted Winner

Kasmir Khaan

@CaptainAmerica16 I get it :D that was funny

CaptainAmerica16

@ÍgjøgnumMeg lol, smooth moves

Kasmir Khaan

is that really you ?

ÍgjøgnumMeg

22:56

Yup

Kasmir Khaan

huh nice moves

ÍgjøgnumMeg

,D

;D

Kasmir Khaan

and gorgeous beard

ÍgjøgnumMeg

hahahaha

Cheers I guess

Kasmir Khaan

I shall one day grow one like that lol

Ted Shifrin

22:58

I've grown a goatee ... I suppose I need to put up a new picture of the old me.

CaptainAmerica16

you have a goatee at this moment?

Ted Shifrin

yup

CaptainAmerica16

I'm having a hard time picturing that.

Kasmir Khaan

selfie now TED

prove it !

Ted Shifrin

I put a new pic on Facebook

CaptainAmerica16

22:58

lol, facebook

Kasmir Khaan

facebook is so 2012

Ted Shifrin

shrug

ÍgjøgnumMeg

What's wrong with facebook?

Jacksoja

am very sure that Kasmir is crazy

Transcript for

$Mathematics$ Mathematics