The h Bar

evil

user218912

okay.

@dmckee It's supposedly very weak, but it can happen in nuclear reactors.

Assuming I wrote the right equation :P

@IceLord I need help. How many days have passed since jan 20th?

2012

user218912

12:24 AM

lol

Question: Do I want to play (and possibly finish off) Final Fantasy 5 or begin watching Daredevil on Netflix?

you know I bought FF7 based on your recommendation and I never got past the first hour

Define first hour

I played for one hour, then stopped.

Because there are varying speeds you can play at and get to various points in 1 hour

12:26 AM

Sure.

Did you fight any bosses?

I'm bad at video games.

Yes

The first one on the bridge?

After setting the bomb?

I got out of that area

I got to some crappy village

Then there was a secret meeting in a basement?

Aeris' house?

12:27 AM

it's been a year

Okay, Sector 7 Slums

Tifa's Bar

That's about 1% of the game done

Maybe 2%

The story gets more interesting after you escape Midgar, which can be a few hours

I think a good speed run time to escape Midgar is about 1:55:00, but casually you can expect around double that

> you guys

not me

you definitely said he writes $\partial_\mu A_\mu$ crap

100% guaranteed

But seriously. My wife is out for the evening and I'm not sure which of those two things to do

@KyleKanos Why?

12:31 AM

Read geometry books

@KyleKanos How many times have you played FF5 already?

@DanielSank Because you'd make a good mod

@ACuriousMind 0.95 times

Give or take a few basis points

@KyleKanos I really mean it, why?

@KyleKanos Then go finish it

I wrote a little bit in the election chat room about why I I'm not running.

I don't think having unilateral close voting is good.

(for me)

All of the actually changes in how I'd use the software seem either irrelevant or negative.

12:33 AM

I'm not sure what more than "You'd be a good mod" I can do

I wouldn't expect the new mods to use/abuse unilateral close votes

(except for those really obvious "Do my work for me" HW questions)

@ACuriousMind Booting up the Wii...

My poor wii hasn't been used in 3 years

You should hack it and turn it into a Wii+SNES+NES+Sega machine

Wii's are un-brickable, which means you can't screw up

@KyleKanos False.

You surely can.

Wii's are the best.

You know what game was epic as FUCK?

Monster Hunter 3---especially when they still had online support.

I've not seen how one can screw rooting it up

12:39 AM

Those monsters were truly epic. Also lots of equipment/best monsters were online-only. So GG :'(

@Danu Flaggable...

Yeah, seriously.

You yelled at me for saying s*&^head, and you drop the F-bomb!?

@KyleKanos I think mods can only vote unilaterally, or so someone said.

That sounds like bad news bears.

Please tell me that's incorrect.

@KyleKanos lol

@DanielSank also yes

(I know from experience)

Yes, you vote unilaterally, but I'd think you'd visit the queues less is all

12:41 AM

@KyleKanos Right.

@KyleKanos In case you weren't kidding, the difference between calling someone a shithead in chat and saying "epic as FUCK" is huge.

So you trade doing reviews for doing flags.

Can't think of a reason I should do that :)

I do promise you

@DanielSank Because I said so

Flags are friggin hilarious

2

12:42 AM

@Danu Negative

However, since that's now like five people telling me to do it, I'm starting to think maybe I'm thinking about this wrong.

I'd do it, but I'd be the worst mod

I tried to understand how being a mod differs from having 20k rep, and it seems flags are the major difference.

I'd probably abuse whatever powers I was granted for the rare instances I visit the site

@KyleKanos You'd ban people for arguing with you on meta :P

12:43 AM

Only if they cannot be convinced by me

The only other things I can see are:

@DanielSank This is the truth. And a fairly popular suggestion to change that is status-declined.

1. having a little more "weight" in policy discussions (because of user perception, not because it actually is that way) because there's a diamond next to the name.

@ACuriousMind re Associated bundles: locally homeomorphic to a Hausdorff space is not sufficient to be a Hausdorff space.

@0celo7 I don't speak gibberish

12:45 AM

2. People will ping me in chat about stuff.

@dmckee am I missing anything?

@ACuriousMind one really has to prove the orbit space is Hausdorff.

Yes, in hindsight, the line with two origins is a pretty obvious counterexample

About being a mod? Or something else.

Yes. I thought of that while walking to the auditorium.

@dmckee Who's that directed at?

12:46 AM

@DanielSank You.

@dmckee Then yes.

I don't think you're missing something, but I'm not sure I know which topic we're on right now.

@dmckee Why I would want to be a mod.

The "advantages" of being a mod

It sounds like the main difference is that I wouldn't do any reviews, but I'd handle flags.

12:48 AM

Not much. If you had a strong feeling that something need attending too right now then mod power let you address that while you're on the site. At the risk of annoying people.

Of course, gold subject badges already let you do the clearest cases like that.

Dupehammer and all.

k

@DanielSank Makes you wonder what all the people get so riled up about, eh?

I wonder if, over a long enough period of time, I'd get a gold subject badge

@ACuriousMind Yes. I'm very, very confused.

You're the only person nominated who I am convinced understands what being a mod actually means.

I think TPG knows

12:50 AM

Some days it feel like another obligation when I already have too many of those. Teach overload, do uni committee work, advise students, try to keep research students working and pointed in roughly the right direction, work on stuff to bolster tenure packet, get ready for in-laws coming next week, ...

Perhaps, but @ACuriousMind is the only person who gave me evidence to believe that he knows.

I gotta go.

Bye, everybody.

Before you go

When's your book gonna be finished?

Chow, but in Italian

ciao?

@KyleKanos Sure, but I'd be faster if you focused more on a few tags

12:53 AM

@KyleKanos Yep. A word I can't spell right with four tries and spell-check enabled. I'd be embarrassed but I've reached the point where I'm just bemused.

Although you might just be unlucky and the initial tags on the questions you answer are bad

I think I also need to have some $n$ number of questions answered too

Okay, I'll never get it

200 answers in a subject

Most I see is 58

And that's in the...homework-and-exercises?!

Yes

Not every H&E Q should be closed

Sure, I was just surprised it wasn't astrophysics

12:58 AM

And a lot of those were earned early on

cosmology*?

Nah, RobJefferies, Kyle & Chris White get the votes on those tags

Though Fluid dynamics is #2 and newtonian-mechanics, astrophysics & qm are all roughly #3

The #2 is kinda surprising

I was surprised to see I was #2 all time in fluid-dynamics behind @JohnRennie. But it would take me a lifetime to catch up

@ACuriousMind So, one has to show Hausdorffness directly?

And @KyleKanos it's nice to see you lurking around again. I haven't had anybody to talk to about various codes

1:05 AM

@tpg2114 Haha, I'm only here b/c the wifey is gone for the evening

Sounds like an exercise for tomorrow, as well as that homeomorphism.

Now that I'm done schooling and have a real job, I don't have time for this site (or hydrocodes, sadly)

I'm ready to be done with school... Must be nice!

Read that as hydrocodone

I think grad school life was easier: could come in later, go earlier, take longer breaks, etc

1:07 AM

@tpg2114 Your lifetime or John's lifetime? ;P

@ACuriousMind First one, then the other.

@KyleKanos I'm starting to look for jobs now. Well, actually jobs are finding me, I haven't started looking yet

But it's getting close to time to make some decisions

Yeah, that is the important thing: deciding what you actually want to do for the rest of your life

Or deciding to post-doc a few more times to delay that decision :)

AFRL is interested in having me work for them. I'm looking at some research labs in France for a post-doc too

Kitware could be cool if I wanted to work on software development

I can imagine AFRL wanting someone with your experience

My thesis work is sponsored by them and I've been having weekly meetings for 2 years now with them. So we're well versed with each other

And I would like to keep working with the guy I'm working with. Just not sure if Dayton, OH is really high on my list of living places. Then again, the money is pretty good

1:18 AM

Yeah, that's Bungle & Brown territory

Good night, guyz

1:45 AM

@tpg2114 my brother lives there.

@0celo7 I left the North to get out of the winters... not eager to go back!

Georgia treating you well?

We fighting you or your similarly named cousins this weekend?

You're playing that podunk school this weekend

Things are going well. Just trying to wrap stuff up and move on

How's school going?

2:05 AM

@tpg2114 Ah, ok. I can't remember who I'm stupposed to hate :P

Too many similarly named schools

@tpg2114 Good. Busy. Trying to accept that I'm a mathematician.

Any particular area of math?

And you're a bit early off to firmly decide fields... Heck, I still want to change mine!

@tpg2114 Geometry of course

I'm trying some baby geometric analysis

2:20 AM

Yeah, highschool geometry is about as advanced as I got with that

My brother just finished his PhD in fixed point theory

@tpg2114 It's really hard to explain what differential geometry is to people

I think. I didn't understand anything he said in his defense or thesis

my gf is taking calc 3 so I'm able to explain some basic concepts to her

@tpg2114 What's fixed point theory?

I know about Lefschetz fixed point theory, and some random fixed point theorems here and there

I have absolutely no idea what he does really. All I could figure out is that fixed points are the solutions in differential equations

Or something

Ah, right

I think we've had this discussion before

(or maybe I have, but not with you; having serious deja vu right now)

2:26 AM

I never really need to deal with the formalities of it. I trust Navier-Stokes has solutions and that my code will iterate to them unless I code it wrong and then it will blow up

there are plenty of things we all take for granted

i.e. consistency of logic & set theory

I take all of math for granted really

:/

Basic addition and multiplication are all I need. And then I just trust that other people have done the hard stuff correctly

that's @IceLord 's attitude too

user218912

2:30 AM

I am offended.

flag it then

user218912

...

user228700

Hihi :-) I was wondering if anybody (other than JR, who is not here at the moment) knows enough chemistry to answer a question of mine..?

What sort of chemistry?

if the chemistry involves principal bundles, I'm all ears

user228700

2:45 AM

@tpg2114 Inorganic Chem.

user228700

@0celo7 Yeah, Idk what u're talking about.

What's the question? No promises I can help, but who knows

user228700

@tpg2114 OK. Do u know anything about the levelling effect of solvents?

Sorry, it's been around 15 years too long for me to remember that one!

lol

wait, how old are you?

2:48 AM

Last chemistry class I took was in 2002 in high school

Christ

I was 5 then

Yeah -- I like to remind the freshmen in the department that their first day of school ever was my first day at Tech

wtf

user228700

@tpg2114 OK, no problem. Thanks for offering.

Don't get a PhD.

2:49 AM

how have you been in school that long

worst-case scenario is 4+6=10 years

'04-'08 for undergrad, '08-present for PhD

:/

Yeah... not in our department. Average length of PhD is 8 years after quals, and it takes 2 years to pass quals

that's crazy

Lots of $$$$ from government and industry provides lots of incentive to uhhh... indenture us... for awhile

2:52 AM

apparently.

Milou

hello physicists.. sorry for interrupting your conversation, but I'm confused with some stuff that I'm not sure I'm understanding how do we do things here :p

Ok, I think the $G$ action on $P\times F$ is free because it is free on $P$.

Milou

but first the ChatJax doesn't seem to work..

I have that tampermonkey icon with the ChatJax on

ok it's working now

first, when we have the action $S=\int L(\{q,\dot{q}\},t),dt$ and we compute $\delta S$, it is equal to $\sum_j \frac{\partial S}{\partial q_j}\delta q_j+ \frac{\partial S}{\partial t}\delta t$, why the term $\ \frac{\partial S}{\partial\dot{q}_j}\delta\dot{q}_j$ is omitted ?

3:22 AM

Hi, everybody.

Milou

@DanielSank hi

by $\delta$ i mean $\Delta$

Is it because when going to the Hamilton-jacobi equation we will get a higher derivative, so it will be canceled?

so we don't mention it anyway?

Sir Cumference

I love the name of this protein

Sonic hedgehog

Sonic hedgehog is a protein that in humans is encoded by the SHH ("sonic hedgehog") gene. Both the gene and the protein may also be found notated alternatively as "Shh". Sonic hedgehog is one of three proteins in the mammalian signaling pathway family called hedgehog, the others being desert hedgehog (DHH) and Indian hedgehog (IHH). SHH is the best studied ligand of the hedgehog signaling pathway. It plays a key role in regulating vertebrate organogenesis, such as in the growth of digits on limbs and organization of the brain. Sonic hedgehog is the best established example of a morphogen as defined...

It's inhibitor? Robotnikin

Physics Meta

3:51 AM

0

Q: Is Minecraft On-Topic?

Long question short: Changing Minecraft's Gravity via Code: StackOverflow, Math, Physics, or SciFi&Fantasy? Actual Question: Premise: So, some quick background on the question I want to answer. The Minecraft world is generally depicted as a large cube (which, of course, doesn't make physical ...

Yo @DavidZ do we have a chat session without a pressing agenda in our future? We'd like to host Jess Riedel for an AMA.

I think doing it during the scheduled discussion sessions worked better than when we did it at an arbitrary time.

user116211

4:09 AM

@DanielSank Did he fix his date yet?

4:27 AM

@MAFIA36790 no

@IceLord I might have to get Naber

I looked in it as a last hope attempt for a proof

I found an exercise that explained everything

@ACuriousMind Yes, I am writing a book

@DanielSank how did you write your "book"

the linear algebra one

Interested in opinions on this meta post about migrating bad questions.

I want to write one

@0celo7 With my brain.

That's not helpful...

4:34 AM

@0celo7 Ask a more specific question.

You wanna know how I got started mentally?

@DanielSank I don't know...how do I get started?

How it's organized?

@0celo7 Make an outline.

Both would be good

Also make sure you know what your goal is.

@DanielSank I don't really have one. All I know is that the literature on principal bundles is bad

among other things

But I also have some thoughts on Riemannian geometry I want to write down

4:38 AM

@0celo7 reminded me of this

I started writing a note, but it was just a few pages

it needs to be more substantial

plus i want to do a BUNCH of exercises from Chow-Lu-Ni and I need someplace to put them

but that's orthogonal to the principal bundle stuff

@BalarkaSen Sorry, I don't get it

"the literature on principal bundles is scattered and inconsistent. i'll write a book to organize it"

yeah?

@0celo7 In that case I have specific advice.

Write short, focused explanations of things you think are explained poorly.

Above all else, establish your own consistent vocabulary and notation.

Of course, the problem is not writing an opus

4:42 AM

Then, five years from now, you may realize you've written the meaty bits of a larger document.

@DanielSank Yes, this.

I want to have a consistent notation.

Good.

That's a major reason why I want to write it, too

Also, if you're starting the point in your life where you're going to start documenting stuff, I recommend you familiarize yourself with how to structure your TeX documents in a modular way.

For me, simply seeing it in a nice font and good notation makes all the difference

Shameless advertisement :P

4:43 AM

@0celo7 Yes, agreed. Good notation is all too rare.

@0celo7 I wrote that article for a reason, dude.

@DanielSank Would you happen to know about neutron ranges?

@0celo7 nope

Don't even know what that means.

I know a little about QFT, but nothing about actual subatomic particles.

I'm taking a nuclear physics class and they randomly want me to do something with neutron mean free paths

I don't know if I should look up the range online or what

ah, wiki has an answer

user116211

@DanielSank I sometimes wonder on what reason I would vote to close such question as is there in the meta post you mentioned above; sometimes I vote to close them due to them being totally maths or sometimes I vote to close them as H/W. I can't conclude which to prefer in such cases...

@DanielSank Next week we have an election chat, but any time after that should be free

user116211

4:53 AM

And we very much do know Maths accepts homework posts more openly than us here.

"Let $(B,M,F,G,\pi)$ be a fiber bundle"

I can't tell if that's good notation or not.

I don't like it

@BalarkaSen Well, you need the total space, the base, the fiber, the group, and the projection.

Yes, it's very formal and all, but it doesn't reflect my picture/intuition of the fiber bundle, hence why I don't like it

@BalarkaSen Wait...what day of the week is it where you are?

4:57 AM

@DavidZ Thank you.

it's Friday

Hmm. I don't have a good grasp of how time zones work

@DavidZ is there an official listing of the chat sessions?

Is it Saturday somewhere in the world?

i.e. when they are?

4:58 AM

We're closer to the Japan so Fridays just started happening. So I think not.

user116211

@0celo7 Don't think so?

well it's friday for me

1AM

I should go to sleep.

user116211

Morning @JohnRennie.

I did make some progress today. This resolution of my bundle problem is very nice

@DanielSank There's the item on the room schedule page

John Rennie

4:59 AM

Morning

However there is no official listing of chat session topics

schedule page...

go here: chat.stackexchange.com/rooms/info/71/the-h-bar?tab=schedule

user116211

@DanielSank You can go to the schedules in the info.

John Rennie

@DavidZ: that chat session is going to need some heavy duty moderation :-(

5:00 AM

yep

user116211

But I don't think there is a detailed list.

@DavidZ That takes me to the main site.

sorry, oneboxing ruined the link

> Let $(B,M,F,G,\pi)$ be a fiber bundle with $M$ and $F$ Hausdorff. Then $B$ is Hausdorff.

Let $p,q\in B$. Suppose first that $\pi(p)=\pi(q)=x$. Let $U$ be a neighborhood of $x$ in $M$ such that $\pi^{-1}(U)\approx U\times F$. Then $p,q\in U\times F$, and they may be separated there since $M\times F$ is Hausdorff. For $\pi(p)\ne \pi(q)$, choose disjoint trivializing neighborhoods of $\pi(p)$ and $\pi(q)$ in $M$. Then the trivializations can be used to separate $p$ and $q$ in $B$.

@ACuriousMind See ^

@DavidZ :O

5:02 AM

Now you're proving that the base is Hausdorff? Huh?

One simply shows that the associated bundle is a generalized fiber bundle.

How do you click to that page?