The h Bar

0celo7

4:00 AM

@BalarkaSen I'll look into it.

Bernardo Meurer

@0celo7 Sobolev embedding sounds like a sex position

Slereah

What about degenerate manifolds

0celo7

What does that even mean?

Balarka Sen

stratified ones are better

ACuriousMind

^

Slereah

4:01 AM

I forget the correct word

Manifolds with possible singularities

0celo7

Why are they good in the first place?

Slereah

Like cones and whatnot

Bernardo Meurer

@0celo7 I'll sobolev your space babe

0celo7

Why can't topologists just be happy with one kind of manifold

@BernardoMeurer I'll use that as a pickup line

Bernardo Meurer

@0celo7 It could probably work, you know?

ACuriousMind

4:02 AM

@0celo7 Because so many natural constructions applied to manifolds aren't manifolds (consider e.g. the suspension)

Bernardo Meurer

"Are you a non-hausdorff manifold?"
"No, why?"
"Because I've never seen anything like you"

0celo7

@ACuriousMind Maybe it's because I have no interest in algebraic topology, but I've never been sitting there and thought "yo it would be cool if I could suspend a manifold."

Bernardo Meurer

I should get more girls

0celo7

@BernardoMeurer I sent you a text

I have a circuits test tomorrow

@ACuriousMind how do I circuits?

Slereah

"In particular one can erect a basis of any fiber"

heheheh

ACuriousMind

4:06 AM

@0celo7 For another case, consider stuff like orbifolds. Sometimes you want some kind of "singularity" while still having some of the tools applicable to manifolds available

0celo7

@ACuriousMind I'm just hating because it hasn't shown up in stuff that I want to work on

ACuriousMind

Fair enough

Bernardo Meurer

Orbifold sounds like a boring toy

ACuriousMind

Beats a potato every day

0celo7

@ACuriousMind You were hating on measure spaces

If I get that thing I applied for the other day I'll be doing measure theory all summer

ACuriousMind

4:08 AM

Ew Good for you :)

Bernardo Meurer

@ACuriousMind Bet you can't run linux on an orbifold

0celo7

@Slereah I tried reading Wald but got bored 20 pages in

Bernardo Meurer

and subsequently doom

Slereah

The QFT Wald?

0celo7

obviously

Slereah

4:09 AM

yeah it's not a fun read

0celo7

@BernardoMeurer you need to come to TN and tell QM girl she's a non-Hausdorff manifold

and I can swoop in and clarify the relevant topology terminology

Balarka Sen

Really ...

What a lame plan and a lame goal

Slereah

"Any vector bundle has global sections, although there may be no global sections which are everywhere non-zero"

Where is the proof dang it

0celo7

@BalarkaSen excuse me, how would you get QM girl's number?

@Slereah zero section

Balarka Sen

I wouldn't

0celo7

4:14 AM

lots of compactly supported sections can be constructed via a partition of unity

Balarka Sen

@Slereah For example of the latter, Moebius strip

0celo7

Why not the tangent bundle of the sphere

Balarka Sen

Yeah, why not the normal neighborhood of an exceptional divisor in a blowup construction instead!

(That actually is an example and not a random string of words)

0celo7

because he doesn't know algebraic geometry

Balarka Sen

Blowup is topology. Connected sum with bar{CP^2}

Slereah

4:17 AM

If you're gonna use Latex remember the $

0celo7

@BalarkaSen what is the bar for?

Balarka Sen

orientation reversed

0celo7

I didn't know there was a natural orientation

Balarka Sen

S^(2n+1)/S^1 is CP^n. Orient the former as the unit sphere in R^(2(n+1)) (which has a natural orientation aka right hand rule) and quotient

In any case the point is CP^2 and bar{CP^2} have different orientations, not that there is a specific god given orientation and we're reversing it

Slereah

"A Whitney sum bundle $\lambda \oplus \lambda$ whose typical fiber is a direct sum $V \oplus V$"

The hell is a Whitney sum bundle

0celo7

4:27 AM

@Slereah You should be complaining that they're not giving you the trivializations

Slereah

I think I'm gonna stop reading that paper

It's all definitions and no proofs

0celo7

do you know the definitions already?

Slereah

Not all, no

0celo7

@Slereah sigh, what are you trying to do here?

have you finished Jost already?

Slereah

"Exciting development began in the 1960's with the realization that the mathematician's fiber bundles and the physicist's gauge theories were essentially identical"

Exciting

I have not

0celo7

4:30 AM

have you stopped reading?

Slereah

Not yet

I just lack focus

Balarka Sen

If you want to learn vector bundles learn from Hatcher

Slereah

Let's procure it legally

0celo7

it's free on his website.

Slereah

Robin Lee Hatcher A Carol for Christmas (The Burke Family Series #1)

That one?

Balarka Sen

4:32 AM

VBKT is on his website

Slereah

ah yes

there we go

Balarka Sen

Chapter 1 contains essentially all the fundamentals you'd ever need I think

I also like Chapter 3 but I don't think it's relevant for you

0celo7

@BalarkaSen connections?

Slereah

Well I should learn about Stiefel Whitney classes

0celo7

no, you don't need to give geroch's spin structures proof

Balarka Sen

4:36 AM

@0celo7 That's more on the realm of geometry, not topology. But that a decomposition of TE exists into a vertical and horizontal component is a nice thing to note; anyone can pick that up at some point in their life

I understand spin structures through S-W classes

obe

how do you deal with sleeping in the same room as other ppl. (dormitory)

seems scary.

Balarka Sen

you just doze off, or you keep awake

simple as that

obe

I'm not a light sleeper so I'm afraid of falling asleep

dunno what they will do to me...

0celo7

Huh?

You've been at school for months

obe

different residence

xD

seriously though

0celo7

4:41 AM

Seriously what?

obe

what should I do to lower my chances of anything bad happening

just stay awake?

Balarka Sen

get some cocaine

0celo7

@obe sleep with a knife

obe

I can't do that.

0celo7

why not?

I do

obe

4:42 AM

because it's a university residence?

0celo7

What does that have to do with anything?

obe

you'll get expelled

0celo7

why?

obe

because you're not allowed to have weapons on university grounds.

0celo7

lmao canada

I guess you're screwed

literally

obe

4:44 AM

fuck

:(

what do i doooooo

0celo7

try not to look too appealing

don't weak provocative clothing, etc.

obe

provocative? I'm a dude

and that's the least of my worries

what if there is a psycho

0celo7

then what the hell are you worried about?

Balarka Sen

be a psycho too

0celo7

^

obe

4:46 AM

dunno how

Balarka Sen

listen to "1. Outside"

0celo7

@obe on your first day, smash a mirror with your fist

then no one with mess with you

obe

ehhh i'm skin and bones basically

0celo7

@BalarkaSen link?

Balarka Sen

@0celo7 There you go. It's an album but I can tell you my favorites if you want

obe

4:48 AM

the kind of advice I wanted was sleeping advice

how should I sleep

to be alert

any tricks?

0celo7

@BalarkaSen Bowie? I was expecting brutal death metal.

obe

(while not getting sleep deprivation)

Balarka Sen

It's more psychologically disorienting than brutal death metals, really!

0celo7

@obe Stop begging for attention, you're going to be fine.

Balarka Sen

(I have heard some of the latter in recent days and like some of them)

obe

4:50 AM

I know I will be fine, if I didn't I would never have agreed to it.

but there is that off chance...

0celo7

then you die or whatever

obe

:(

0celo7

afterwards, you move on

or, not, if you're dead

Balarka Sen

die and deal with it

0celo7

^

Balarka Sen

4:52 AM

if y'know what i mean

Slereah

"With hindsight one can see that the first use of a fiber bundle in physics was in fact the Kaluza Klein theory."

obe

ok thx

0celo7

Look, I'm not saying become a nihilist (I hate nihilists). But if you do die, then it doesn't matter anymore.

@Slereah Huh?

Wasn't KK after GR?

obe

wow dude if I only have one life then why would I waste it like that when I could be more careful.

0celo7

GR uses the tangent bundle.

@obe Because once you die it's all gone anyway.

obe

4:54 AM

then why do anything lmao

just sleep all day

Balarka Sen

that's the spirit

0celo7

because you'd get yelled at by parents and it's unpleasant

@obe why would anyone find out if you have a knife, anyway

obe

@0celo7 where would I even place it?

0celo7

under the pillow

get an automatic

out the front is good

obe

and risk stabbing my face, no thx.

0celo7

5:01 AM

why would you stab your face?

obe

in my sleep

0celo7

then put it on your nightstand

obe

lmao everyone would see it

0celo7

put it away in the morning

take it out at night

this is not algebraic topology

obe

and who's to say someone else won't see it and take it for themselves

0celo7

5:02 AM

oh my god

you're insane

you deserve to be stolen from

obe

wow

Balarka Sen

you should really hear that album out instead of trolling obe

0celo7

@BalarkaSen I'm making a formula sheet right now, no music

Balarka Sen

oh well. your loss

obe

I realized something

ppl can't really choose when to wake up, so all I have to do is sleep the latest and wake up the earliest.

0celo7

5:05 AM

@BalarkaSen should we tell him?

obe

tell me?

Balarka Sen

we should

you should do it, i can't bear to pass on the news

0celo7

@obe I'll tell you on Skype

I would get banned for saying it here

obe

ok, tell me.

Balarka Sen

Err, what you have in mind presumably was not what I was planning to tell

So I will have no part in this

obe

5:08 AM

hurry I need to sleep

class at 7

Balarka Sen

I was just gonna say you're paranoid

obe

thx I feel better now.

Balarka Sen

Get to know your roommate better and you should have no problem

obe

yea

DanielSank

6:15 AM

Hi, everybody.

Sir Cumference

6:54 AM

Howdy

William Budd

8:09 AM

Allow me to vent that I don't understand why people are upvoting the top answer to physics.stackexchange.com/questions/310472/… even though I addressed/refuted its argumentation in several ways already...

Slereah

Is it me or do manifolds definitions oscillate between the atlas being from $\Bbb R^n$ to $M$ and the opposite?

I mean it's invertible so it's fine, but it's a bit unnerving

user228700

10:05 AM

Hi, everyone :-)

user228700

@JohnR: How was ur birthday?

John Rennie

@Kaumudi.H Morning. Yesterday was a quiet day. I'm out celebrating tonight!

user228700

Nice! :-)

skill patrol

Happy birthday!

user228700

Did u happen to receive any presents?

John Rennie

10:07 AM

@skillpatrol Thanks :-)

@Kaumudi.H My mother sent me a cheque with instructions to spend it foolishly! So she is funding tonight's extravaganza.

user228700

That's awesome! :-)

John Rennie

Other than that life goes on as normal. No new laptops (sigh).

user228700

Haha, OK :-) What book are u currently reading?

John Rennie

I've just finished a really funny book called Glasgow Fairytale

amazon.co.uk/dp/B00IQY6XC6

But it's funny mainly because of all the in jokes for anyone who knows Glasgow so I suspect you'd just find it mystifying.

user228700

Hmm, OK, it sounds...good.

user228700

10:13 AM

@JohnRennie Ohh, OK...

user228700

Speaking of books, have u ever been on a road trip?

John Rennie

It depends what you mean by a road trip.

In my student days I rode a motorbike from Cambridge to Rome (and back).

user228700

Rome?!

skill patrol

:O

John Rennie

yes, Rome

skill patrol

10:15 AM

How...adventurous.

user228700

@JohnRennie What? Motorbike?

John Rennie

Yes, in my student days I rode a big motorcyle.

4

user228700

skill patrol

Like CC rider :P

John Rennie

CC Rider?

user228700

10:17 AM

Did ur motorcycle have the powers to transform into a plane to fly over the sea?

John Rennie

@Kaumudi.H I crossed the channel on a ferry :-) No, I didn't own an amphibious motorcycle :-)

user228700

Ah, OK :-) Did u go on ur own?

John Rennie

The route you show is the most direct, but because it was a holiday I took a deliberately circuitous route to visit as many countries as I could.

user228700

How old were u?

John Rennie

From memory I visited France, Belgium, Luxembourg, Germany, Austria and Italy.

user228700

10:20 AM

John Rennie

It was during my PhD. I can't remember exactly but I would have been in my early 20s. Maybe 22 or 23.

skill patrol

Elvis - CC RIDER - Rare Version

►

user228700

@JohnRennie Wow, I see. Did u go on ur own?

John Rennie

It isn't that adventurous. Motorbiking through Europe is hardly exploring the wild unknown.

I went with a friend who was also doing his PhD.

user228700

I see. That is really something else. Dyou have any diary entries/videos (was it possible to easily record videos back then?) from the trip?

John Rennie

10:23 AM

I did keep a diary and I still have it. I keep it as a reminder that I wasn't always middle aged :-)

user228700

Haha, OK, that's great :-)

user228700

What kind of motorcycle was it?

John Rennie

No videos - smartphones didn't exist in 1984. There are some pictures somewhere but over the years I've misplaced them and can't remember where they are.

user228700

Right, of course, OK...

John Rennie

I used to buy new motorcycles all the time, so I'm not absolutely sure, but I think it was a Suzuki GS850.

Slereah

10:25 AM

So @JohnRennie

user228700

Nice :-) I asked out of curiosity, please don't assume that I know the first thing about motorcycles.

Slereah

Do you feel a day older than 56 now

John Rennie

@Slereah :: shrug ::

user228700

This is a map of the route from Chennai to Pondicherry:

John Rennie

@Kaumudi.H I think the motorbike would do over 140 mph flat out, though I didn't ride it flat out that often. It was far from the maddest motocycle I ever owned.

skill patrol

10:28 AM

user228700

And as is clear from the picture, the road is right along the coast, providing magnificent scenery for those who are bored and stuck on the road.

user228700

Would it be completely mental to try to navigate the distance using a bicycle?

John Rennie

@skillpatrol choppers are really an American phenomenon. Pretty much all the European bikers rode (or did in the 1980s) racer style bikes. Our roads are generally more suited to racers.

skill patrol

I see.

John Rennie

10:31 AM

@Kaumudi.H no, of course not. I'm not a huge fan of long distance cycling, but I have friends who regularly cycle long distances for fun. That's long as in they take two or three days to complete the trip.

user228700

Heh, but here's the catch--I'll need to cover the whole distance in a single day.

Slereah

maybe they're just really slow

John Rennie

@Kaumudi.H If it's a good road and not too hilly 156km in a day should be easily doable. However I'm guessing the roads aren't that great in which case you might be wiser to arrange a stop halfway.

And anyway part of the fun would be to admire the scenery. You don't want to be riding hell for leather the whole way. Doing it in two days gives you a chance to enjoy the scenery along the way.

user228700

No no, the road is excellent, for the most part.

user228700

But like you said, yes, stopping is a crucial aspect of "road trips", as I've heard from other people as well...

user228700

10:35 AM

Hmm. I desperately want to go in the summer but in the first place, it will be so, so sunny. Secondly, I don't think any of my friends will be home from university.

user228700

Not only is the journey itself quite extraordinary, the destination is equally awesome!

John Rennie

I quite like cycling on my own. It's very meditative - you slip into a kind of trance/daydream. On the other hand having friends around is nice when you stop for meals etc.

user228700

It is meditative. However, after having been completely alone in these past months, I don't think I will crave more alone-time in the summer.

skill patrol

Cycling is a serious sport.

user228700

If I were a boy and much less responsible than I really am, there wouldn't even be a question of whether or not my parents would allow it--Pondicherry is a union territory and the legal age for consuming alcohol there is 18 (::Whispers:: I'll be 18 in April)

user228700

10:40 AM

But mostly, my parents might not concede because of the long distance and the sun.

skill patrol

Are you planning to go out drinking on your birthday?

user228700

Nope.

user228700

I have an exam on the day after my birthday x'D I am merely hoping to convince my parents to let me go cycling to Pondicherry, for the cycling part itself.

John Rennie

@Kaumudi.H You're south of the equator aren't you, so presumably it gets cooler in the summer.

skill patrol

What's the legal driving age?

user228700

10:43 AM

@JohnRennie U couldn't be more wrong, sir! In the summer, it gets to nearly 37 degrees here!

user228700

@skillpatrol Uhh, 18. And u might just have given me a new idea...

skill patrol

...now that's a good idea :-)

John Rennie

@Kaumudi.H I'm not sure I'd be keen on cycling 156 kilometres ina temperature of 37C :-)

user228700

@JohnRennie Exactly...

John Rennie

What time of the year is it coolest?

skill patrol

10:44 AM

Winter :P

user228700

Um, there is no concept of "seasons" in Chennai :-P

John Rennie

I guess you're too close to the equator for the temperature to change much ...

user228700

It remains fairly hot throughout the year and in December, it rains for a bit, and the temperature comes down to about 21 degrees.

skill patrol

No monsoon season?

user228700

@skillpatrol Unfortunately, nope .

John Rennie

10:46 AM

Go in the cyclone season :-)

user228700

:'-( There isn't much to do here, inside the city itself. Well, I'm hoping to beg my parents for a proper camera (the one on my phone isn't so great) and go around Chennai, visiting some of my favorite places and clicking pictures.

user228700

...but again, I'm not sure if any of my friends will be here and I might just have to do that on my own.

user228700

As of now, this is literally it (my to-do list) --

user228700

If I do get that kindle, I'll read the books on my to-read list!

user228700

10:51 AM

And if I'm able to download the movies on my to-watch list, I will watch those.

skill patrol

Do you have an i-watch?

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