The h Bar - 2016-06-24 (page 1 of 3)

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12:13 AM

@Slereah is it possible for an acausal spacetime to be stably causal if we remove one (1) CTC

I think Sanchez has a spacetime with only one CTC

Oh no

nvm

user image

mb that one

Not sure how you would remove it, tho

Removing a point would make it non-distinguishing

1 hour later…

1:17 AM

@Slereah what's that again?

the 2016 GTM design is disgusting

0

Q: Revise zigzag question?

I posted this question. Is running in a zigzag helpful in avoiding being shot by an arrow? It has at least 7 upvotes, and the answer has at least 6 upvotes. I want to give the answerer a bounty. I can't because my question is off-topic. How can I revise my question to be on-topic?

discussion scope closed-questions review reopen

like gone-off cream

1:35 AM

Is gone-off even American English>

1:56 AM

@Slereah check it link.springer.com/book/10.1007/978-3-642-61876-5

@ACuriousMind Do you know what manifold $\mathrm{SL}(2,\Bbb R)/\mathrm{SO}(2)$ is?

2:16 AM

@ACuriousMind Hmm. I recall $\mathrm{SL}(2,\Bbb R)$ being homeo to the interior of a solid torus.

So maybe an open disk in $\Bbb R^2$?

2:58 AM

Please someone can tell, " Can we know Total Energy and position of a particle together?" In yes or no? I don't know about Hamilton and all.

3:23 AM

@ACuriousMind What's the rationale for using "one to one" over "injective" and similarly for the other one

4:10 AM

Hawkins tell we can go in future if we go near black hole, we can slow time of us and return to earth in future. I ask what is the need of all this. We can just cryo-preserve a man. And wake him 100 years later. He will find himself in future.

5:08 AM

Hey @JohnRennie, and all other brits here, my condolences :/. I'm pretty shocked and deeply saddened that this just happened, and I suspect many here will share much of my response. I fear, very much, for the the many irrevocable damages that the future must bring now, and I'm not sure at all that there will be a way to avoid or even soften them. Sad day indeed.

7

It is absolutely astonishing. Words fail me.

Scotland voted overwhelming to remain part of the EU, so the result will inevitably trigger a new independence referendum, and this time Scotland will vote for independence. So we've just seen the breakup of the UK as well as its exit from the EU.

As for what happens now, the truth is that no-one has any idea what is going to happen now.

Indeed. And a much more fragile, divided, and insecure Europe in a time of rising challenges.

I can't see any winner here, only plenty of losers.

The pound has now fallen to its lowest value for 30 years. I think that tells us how the world in general sees the result.

To be honest I've been trying to refresh those pages but most of my usual currency trackers are completely overwhelmed.

God help us when the London stock market opens

5:16 AM

For sure. Boy, is this ever one of those "interesting times" that makes the Chinese proverb way more of a curse than a blessing.

5:52 AM

I have revised my question many times. I am in danger of getting blocked. Can you reopen and upvote my question on physics.stackexchange.com/questions/262680/…

6:49 AM

I have revised my question many times to provide research effort and example. I also provide an explicit mathematical equation. I am in danger of getting blocked. Can you upvote my question to neutral?

7:39 AM

"Although the spacetime considered in this work admits CTCs for sufficiently large values of time lag τ, their existence has no influence on monochromatic waves"

neat

Tho for free fields it seems to be pretty common that CTCs aren't that important

Since solutions can just superpose

"In this kind of spacetimes, the closed null curves are a set of measure zero and due to the diverging lens property of the wormhole, the strength of the field is weakened by a factor a/2d at each loop in the infinitely looping closed null geodesics."

also that

I guess the big effect for free fields with CTCs is cutting off a class of frequencies

Well it could be worse. After the initial panic settled down the FTSE 100 is down about 5% and the FTSE 250 is down 8%. I say could be worse, but this is comparable to the falls after the 2008 crash and that was followed by a recession from which we still haven't completely recovered.

And the prime minister has resigned, and there are already calls for an immediate general election, and we might get our very own Trump-a-like as our next prime minister. Great.

7:56 AM

Well then you'd better help me with the time machine!

I think I might go back to bed - for a few days ...

8:16 AM

So this paper solves (somewhat) the wave equation for spherical wormholes

It is not pretty

Also he uses polar coordinates instead of bipolar

I think bipolar might work out better, but of course calculating anything with toroidal wavefunctions is a bitch

The basic idea seems to be to split the solution into three parts

Waves coming from infinity, and waves coming from the mouthes

user116211

@JohnRennie: Brexit was inevitable.

user116211

'I want my money back'.

I don't think that's true. The vote was 51.8% leave to 48.2% remain. That's not a huge margin.

user116211

It's an European tragedy that Cameron would quit as UK leaves.

Only by contrast

Cameron was quite unloved

8:28 AM

Cameron's position was untenable. Under the circumstances he had no choice but to resign. And to be fair this is largely his doing. He held a referendum because he didn't think people were stupid enough to vote leave. That was a bad misjudgement on his part.

user116211

so, who will be the next PM?

It will be meee

Or Farage

He will make Britain great again

user116211

Britain First would be happy today.

@Slereah I was going to say don't be silly we'll never elect a buffoon as prime minister, but then there's an excellent chance we'll get Boris Johnson as the next PM.

user116211

What would Jeremy Corbyn do now?

user116211

8:32 AM

Would he resign too?

Well the interesting thing is that Corbyn really supports Leave. He had to be seen as supporting Remain in his role as leader, but he was never enthusiastic about it and for the thirty years before he became labour leader he was opposed to the EU.

So if anything he's in a strong position.

@0celo7 : ask the moderators. Sure you can have a copy, but hey, it might only be an eBook. And it won't be finished any time soon. It will be 6 months at least, maybe 12.

0

Q: Wave equation for odd spacetimes and source terms

It seems to be quite common practice, when solving the wave equation in spacetimes with odd topologies or horizons, to decompose the solution into a sum of the various origins (or destinations) of the waves. For instance, in Hawking's paper on Hawking radiation, it is expressed as the sum of sol...

waves black-holes topology wormholes

plz halp

user116211

8:47 AM

@Slereah Guess, you would get reply from CuriousOne, Timaeus and ?

Well now that JD is back, I can probably expect his standard answer

user116211

in Tavern on the Meta on Meta Stack Exchange Chat, 1 hour ago, by Bart

Brexit. Cameron out. Now let's get Boris Johnson in, and have Trump be president in the US ... I'll head for my Swiss nuclear bunker.

user116211

Really, dark age is coming.

No, it's not going to be a dark age. Some compromise deal will be arranged between the UK and the EU. Growth will be weaker than it would have been for the next decade or so, but armageddon isn't around the corner.

What will be interesting is the effect on the rest of the EU.

user116211

hope so.

user116211

8:59 AM

@yuggib: o/

@MAFIA36790 \o

physics.stackexchange.com/questions/264436/…

now deleted

but was the plain old "I do a logic inconsistency (dividing by zero), and then I get that every b *** s *** t can be true (1=0)"

logic is sometimes a nasty cow

9:26 AM

@JohnRennie Your optimism is enviable, let's hope you're right.

@ACuriousMind we should probably bit a cautious about political discussion in the SE chat, but I have several reasons to believe things won't be that bad.

@0celo7 Since $\mathrm{SL}(2,\mathbb{R})$ is diffeomorphic to $\mathbb{R}_{>0}\times\mathbb{R}\times S^1$ ("Iwasawa decomposition"), that quotient should be diffeomorphic to $\mathbb{R}_{>0}\times\mathbb{R}$ since we really just got rid of the $S^1$.

Despite the evidence otherwise, politicians aren't stupid and won't vote for mutually assured destruction. The UK is a big enough market, both import and export, that all parties will be keen to keep trade flowing.

Plus I suspect the EU have realised they've been pushing the federalist agenda a bit too hard, and they'll back off a bit in case it triggers similar referenda in e.g. the Netherlands.

9:40 AM

Hey @ACuriousMind Did you know that Lang wrote an entire book on $SL_2(R)$? :D

@JohnRennie The Netherlands is never going to leave the EU.

I did not, but I am not surprised

We realize that we depend on the EU very strongly for... pretty much all the monies.

@Danu so does, err did, the UK. I fear your overestimate the rationality of your fellow humans.

@Danu I have it...as all the GTMs ;-)

or almost all of them

;-)

@JohnRennie I'm very disappointed in the UK :\

@yuggib Why do you have all of them? :P

9:43 AM

@Danu because I could take them

in pdf I mean

??

Oh...

Yeah, me too. I have access to that too.

I had the subscription ;-)

@Danu You're disappointed? You're disappointed? I have to live here! :-(

@JohnRennie Heh... Well, I just didn't really expect it to go this way.

user116211

@Danu No one either.

9:44 AM

Neither did I

deep sigh

I suspect the key issue was immigration. The newspapers have spent the last month telling us we can't stop European convicted rapists from coming to the UK and ravaging our fair maidens.

What they don't say is that the vast majority of maidens ravaged in the UK were ravaged by home grown rapists.

user116211

It's official:

user116211

UK is now poorer than France.

@JohnRennie Racism/xenophobia :D

@MAFIA36790 lolwut?

user116211

10:00 AM

@Danu Pound-sterling has fallen down to its lowest in the last 30 years.

@MAFIA36790 Only if you measure wealth by comparing dollar-converted GDP.

wow! full bar

user116211

No 0celot hasn't come yet.

hehe

@MAFIA36790 I've been thinking of buying myself the new OnePlus 3 phone. Since that's going to be 10% more expensive as soon as they get around to updating the web site I've gone ahead and ordered one just now.

10:03 AM

@JohnRennie Nice.

So at least I'll soon have a new toy to cheer myself up with :-)

@JohnRennie OnePlus 3 ? Is that a new thing?

user116211

@kevinTahN. why not google that ;P

I just did

I looks like a cool phone

My OnePlus One died after an unlucky encounter with a stone floor.

10:04 AM

@kevinTahN. if you're a phone nerd you'll already know about the new OnePlus 3. If you're not a phone nerd you won't care about the new OnePlus 3 :-)

user116211

Also, @JohnRennie, that would be really going to adversely affect foreign students studying in England.

lol :)

user116211

The expenses of Oxbridge really became mammoth high.

user116211

From Rs. 3500000 to Rs. 500000 lakhs per annum for UG course in Oxford.

@MAFIA36790 Well no, your dollar or ECU now buys you 10% more pounds sterling, so life in the UK has got cheaper for foreign students.

user116211

10:06 AM

Damn ;(

To less grave matters: Arrrrgh, why does this user ask a question they then themselves close as unclear what you're asking???

Is there an "unclear what you're voting" flag? :P

I feel a bit sorry for Jen. She (he? it?) really tries, but knows so little about physics that most of her questions get closed immediately.

It seems she's in 10th grade

She has more rep points than me

@JohnRennie I'm honestly not sure what to make of this user. It's not the lack of expertise, it's the consistent incoherency of even one-liner comments (and not-responding to well-meaning comments from others) that made me at first think they're trolling, but now I'm not so sure anymore

I don't think she's a troll because I can't see what she would be trying to achieve. I think she is genuinely a 15 year old fascinated by physics but with little knowledge of it.

And to fair there is some interesting physics in the question you linked, though I suspect that's accidental rather than intentional on her part :-)

10:14 AM

@JohnRennie But why vote to close your own question? The question presumbly makes sense to her, doesn't it?

I didn't even know users can VTC their own question as anything other than a duplicate below 3k

user116211

> UK universities rely on the EU for around 16% of their total research funding, and are disproportionately successful at winning EU-awarded research grants. This has raised questions about how such funding would be impacted by a British exit

user116211

But:

@MAFIA36790 this isn't a simple issue. In the EU the big economies (Germany, UK, France, in roughly that order) subsidise the smaller economies. This is as it should be, but it does mean the UK gets less back from the EU than it puts in.

user116211

> non-EU countries such as Israel and Switzerland signed agreements with the EU in terms of the funding of collaborative research and projects, and suggested that if Britain left the EU, Britain would be able to reach a similar agreement with the EU, pointing out that educated people and research bodies would easily find some financial arrangement during an at least 2-year transition period which was related to Article 50 of Treaty of European Union

So the UK government can certainly afford to make up the lost EU funding for the universitites. The question is whether they will do.

user116211

10:18 AM

@JohnRennie They will have to do.

They would be very foolish not to, but they certainly don't have to.

user116211

Would there be again another election?

I would guess not.

I suspect everyone will want to calm things down for the next two years. The opposition (the Labour party) would struggle to win an election right now, so they won't be keen to hold an election immediately.

What will be really interesting is if Scotland decide to hold another independence vote.

Scotland benefits massively from EU funding and the Scots voted to remain in the EU by a large margin. They may well feel they don't want to be dragged out of the EU by England.

user116211

@JohnRennie You mean another independence referendum? Well, it can happen within 2 years and they would vote for independence this time and soon join EU after that.

user image

Yellow is Remain and Blue is Leave - there's a pattern here :-)

10:26 AM

lol

So clear!

What surprises me is that there's no such pattern with Wales and Northern Ireland. Is there an easy answer for that?

@Bass I'll send you those notes now.

@Danu Cheers :)

Wales is a bit of a surprise. Wales also benefits a lot from EU funding and I would have guessed they would vote to remain in the same way the Scots did.

Am I being unfair here?

@JohnRennie Since you closed the question. I'd request to quote the answer from the "so-called" duplicate question you linked to this. If you can't do that, please have the basic courtesy to acknowledge your ignorance and reopen the question. Otherwise this is just plain use of your reputation here, to close question you don't personally like. This site isn't here to run according to you, neither you pay anything and even if you simply leave, things won't change much, since your answers aren't actually on questions, no one else can answer. — Isomorphic 9 mins ago

user116211

Gerry Adams has already tweeted that they should have a referendum to join the Republic.

10:34 AM

@Bass Done. As I said, feel free to make comments/point out mistakes, so that I can help/correct the notes.

@JohnRennie ...what?

@MAFIA36790 in NI people kill each other over this issue. We can but hope things don't get to that stage. I think Gerry Adams is playing with fire.

@JohnRennie So the republicans want to unify Ireland, why do they vote Leave? I don't see why an isolated UK would be an advantage for a unified Ireland.

Or do they hope Scotland leaves UK, so they can too?

@Danu Thank you!

@Bass Oops, I got that the wrong way round. The Republicans voted Remain and the Loyalists voted Leave.

→ 1 message moved to Trash

@JohnRennie I see :) But I'm still not sure if I understand their reasons. What's the connection between Brexit and the unification of Ireland?

10:39 AM

The economies of Northern Ireland and Eire are very closely tied together. Once the UK leaves the EU there will be tariffs on any goods crossing the border, and that's potentially disastrous for lots of businesses on both sides of the border.

So the Republicans are arguing that because the English don't like Europe it's going to drag the Northern Ireland economy down with it. They claim NI should reunify with Eire to stay in the EU.

And to be fair they have a point. But they're playing with people's lives and that's not a good thing.

Check the bounty statement :-)

36

Q: Is the wave-particle duality a real duality?

I often hear about the wave-particle duality, and how particles exhibit properties of both particles and waves. I most recently heard this in this video. However, I wonder; is this actually a duality? At the most fundamental level, we 'know' that everything is made up out of particles, whether th...

quantum-mechanics quantum-field-theory wave-particle-duality duality

@JohnRennie No, you're not unfair here - I think it is a sufficently close duplicate

@JohnRennie Yeah, I already flagged that.

I've suggested that Isomorphic join the chat room to discuss it, but he/she/it seem more interested in venting than discussion. Oh well.

Happy UK independence day everyone :( :( :(

@JohnRennie What a ridiculous, childish reaction from Isomorphic.

@Danu it's very easy for tempers to flair online. I wouldn't read too much into it.

10:52 AM

@JohnRennie "It's easy for tempers to flair online" is a regrettable fact, not an excuse. People need to stop treating digital forms of interaction as somehow unencumbered from the normal rules of human interaction.

@Isomorphic: hi

Yes, say

Hello

Please quote the answer

I don't understand what you mean by quote the answer

There's nothing wrong with your question

I mean, if the answer to my question already exists on the website. Please tell me where it is.

It's a perfectly good question and something that puzzles lots of people, but it is a duplicate

If you want to discuss the wave-particle duality here I'm happy to do this as I think it's very interesting.

10:59 AM

You tagged the question as a duplicate. By this logic, any question that deals with any specific confusion regarding length contraction, you'll link it to the wikipedia entry of length contraction.

Yes, and you presuambly agree since you placed a bounty on the question I linked.

You may feel the duplicate doesn't have a good answer, but it is nevertheless a duplicate

@Isomorphic 1. Whether the question is a duplicate has little to do with whether there is a sufficient answer to the duplicate. 2. juaranga's answer explains perfectly well that there is no "wave-particle duality" and you just need to stop thinking in terms of Newtonian particles and classical waves.

I am tempted to add my own answer to that duplicate, though you seem to feel I don't have anything useful to contribute

But if you want me to try and explain here I'm happy to have a go

Please explain.

It's because what we call particles are not really particles and what we call waves aren't really waves.

The fundamental particles are described by quantum field theory

Now this isn't strictly true, and ACuriousMind will shout at me for saying it, but you can think of particles as excitations in a quantum field.

For example there is an electron quantum field that fills all of space and all of time. What we think of as electrons are the result of adding energy to this field.

user116211

11:05 AM

Boris booed while coming from his home in London.

Am I making sense? ...

What is wrong with the way, I am seeing the theory

@Isomorphic 1. I have no idea what a "stackexchange Nazi" is, but I would prefer you don't try to insult me. 2. The goal of StackExchange sites is not to help specific people, but to provide a useful and permanent repository of good questions and answers. Specifically not bending the rules for the sake of individuals is what makes the SE model so different from fora and other approaches - and so successful.

@Isomorphic your approach can't explain the creation and destruction of particles. QFT does explain this, because particles can be created and destroyed by adding/removing energy from the field.

user116211

@Isomorphic Also, behave nicely; don't rant unnecessarily.

11:10 AM

QFT is so widely adopted because it works so well

@JohnRennie Upto the experiments, I'd study in a regular QM course.

user116211

And not with such words like Nazi; they are objectionable, dude.

@Isomorphic If I leave out such experiments, that cause QFT to be invoked

@ACuriousMind You think websites like Math and StackOverflow are successful because of adhering to such rules? You're kidding me.

You seem to be suggesting we invent an effective theory that describes particles in a very limited regime. We could do that, but why would we? It just makes things more complicated.

@ACuriousMind Physics isn't a successful website. You're depriving new students of a valuable learning tool, just because you want to follow certain rules and satisfy your ego

11:12 AM

For the record, I would call Mathematics a very unsuccessful site in the sense of providing an extensive/useful repository of knowledge.

@JohnRennie I think we did that. It's called Bohmian mechanics :P

I regard Physics as much better (in this aspect).

Mathematics is mostly a huge collection of random homework questions, basically.

user116211

Does Bohemian Mechanics come in agreement with SR?

user116211

I don't think it can give a unified theory.

@Isomorphic We're trying to offer valuable (I hope) learning right here right now ...

11:15 AM

Alright, great

I've lost track of where we've got to. Has what I've said so far been of any help?

@Danu That is why there are two of them. Unfortunately, theoretical physics closed down and all the people who were there are expecting the model of mathoverflow to be applied on physics stackexchange.

@JohnRennie Thank you, but this isn't helping me at all.

@Isomorphic No, not really. I'm all for low-level questions (just have a look at my most upvoted answers, for instance), but I do not like answering homework problems.

user116211

@Isomorphic Have you heard of Physics Overflow?

@Isomorphic OK I'm not sure where we aren't connecting. Perhaps you could offer some input.

11:19 AM

@Isomorphic I don't want to "satisfy my ego" or "follow rules" as goals in themselves. I follow the rules because I believe they are conducive to worthwhile questions being asked. And if you look on our meta you will see extensive discussion about why these rules are in place.

@JohnRennie Look QFT took some time to be developed after QM, but before that people had some understanding of the conceptual underpinnings of the subject. I'm trying to see how they did it.

@Isomorphic conceptual underpinnings of what? Wave-particle duality?

@ACuriousMind The very fact, that you don't seem to be using common sense and want to invoke some meta posts to win an argument regarding functioning of a trivial QnA website, shows the difference in the way of our thinking.

@JohnRennie I don't see wave particle duality working for cases other than a single particle.

> trivial QnA website

@Danu You don't like answering. How about leaving it alone?

11:21 AM

I don't think you really understand this site.

@Danu Really? Is it really that complex?

@Isomorphic Oh, I also don't like wasting my time on reading them when I'm looking for interesting posts.

@Isomorphic Okay, that's the third message from you that's nothing but silly assertions about me "stackexchange Nazi", "satisfy your ego", "don't seem to be using common sense". I will not respond to you further.

user116211

@Isomorphic Actually, you don't want to understand the site.

@Isomorphic can you elaborate on that as I'm not sure what you mean.

11:23 AM

@JohnRennie Lol

@JohnRennie Ok you win

user116211

o.O

I'm not trying to be clever. I genuinely don't uderstand what you mean by I don't see wave particle duality working for cases other than a single particle

Are you thinking of experiments like Young's slits?

Example of wave-particle duality working: Photo-electric effect (many photons & electrons involved).

I just realized that chronology protection doesn't care about closed timelike curve

It is only specifically closed null geodesics

Since the SET is $\approx \sum_\gamma \frac{f(x,y)}{\sigma^4_\gamma(x,y)}$

and the geodesic length will only be 0 for a null curve

I think wormhole spacetimes only have like one closed null geodesic

It's the one made by connecting the centers together

But that's enough to sour the situation

Since otherwise wormholes are pretty divergent lenses

user116211

@Isomorphic: So, this is how you put bounty with such heavy nonsense ranting?

11:36 AM

@JohnRennie I think you "won" :P

You can't win debating with cranks, for you are not playing the same game :p

→ 2 messages moved to Trash

0

Q: Constrained motion

All speed shown are with respect to ground. Then we have to find the speed of block B with respect to ground. I tried it by two methods, but got different result why?

homework-and-exercises newtonian-mechanics spring

@Isomorphic just writing @Danu in a comment does not ping me. Just so you know.

user116211

@Danu, it is fruitless explaining anything to him; better ignore him.

11:42 AM

By the way, I'm downvoting + voting to close this question because I think it shows insufficient effort: At least bother to type it up!

@Isomorphic that's a homework question, and the site policy is that we don't want questions like that on the site. As it happens I agree with that policy, but I didn't create that policy - it existed before I joined the Physics SE.

We all know @JohnRennie secretly runs Stack Exchange

Alright, have a great day and @JohnRennie I'm sorry for the insults.

@Slereah I thought @DanielSank is the puppetmaster!

user116211

@Isomorphic BTW, it was not John who VC it; it was me.

11:44 AM

This is big news...

Many layers to this plot, @ACuriousMind

user116211

@Slereah Nooo! It's Lumo ;((

Because I tried hard to make a point clear to you, but all you are throwing at me are policies. You're the moderators. You can choose not to follow it to the point that they become a pain and obstruction for someone. Anyways, it is all futile for me to try to change anything around here. I understand your arguments, but I just don't think they're good enough. There's no say of someone who is actually trying to learn things, in the working of the site,

so, there are always going to be such issues. I hope you don't come with, we're all learners here crap, to defend your position. You know what I mean, in any topic of physics, there's a certain threshhold that you need to cross so that you can start asking question that an expert of that field finds interesting to answer.

@ACuriousMind Should that not be $\Bbb R_{\ge 0}$?

@Isomorphic None of us are moderators on this site, by the way.

11:52 AM

@0celo7 no

The Iwasawa decomposition is a diffeomorphism, but not a group homomorphism, if you're wondering why the zero is "missing"

@ACuriousMind But I swear to god it's homeo to a torus

But you're simply shrugging of your shoulders and also not allowing anyone else to be able to answer such questions for someone who hasn't crossed that threshold yet. You are learning a QnA, where the person who answers controls the kind of questions he likes to be asked. Questions like why does a chair has 4 legs are entertained, which show that the OP hasn't ever studied seriously the phenomena of toppling and probably doesn't even understand what normal reaction is, whereas students

Or is that a torus

who actually struggle are disencouraged.

@Isomorphic That's the way the site is, and it was a deliberate decision to make it that way. There are sites that will help with homework but this isn't one.

11:55 AM

@Danu You all have enough rep and with rep comes moderation powers. I hope you know that, since you use them all the time.

user116211

@Isomorphic they are entertained because they have genuine physics query in them.

@MAFIA36790 They're stupid questions.

@Isomorphic ...sure, but there is a big difference between having rep-based moderation powers and being a moderator.

user116211

We encourage conceptual query and not just petty trivial homeworks which just want how to solve.

@Isomorphic Oh, don't worry, I downvoted that question too.

11:56 AM

@ACuriousMind I'm stupid, what does $\Bbb R\times\Bbb R_{>0}\times S^1$ look like

@0celo7 s.It's the upper half plane with a circle attached to every point.

Stop bitching and go to Physics Forum

Jeez

@ACuriousMind Yeah I know that

@MAFIA36790 Yes, chairs are pretty conceptual than helping someone figure out what is relative velocity.

But that does not help me in the slightest

11:57 AM

@0celo7 Well then tell me what you actually want

Are you telling me that my torus thing is wrong?

Yes, it's not a torus.

@ACuriousMind Sigh

user116211

@Isomorphic As I said, you never really want to understand what we meant by conceptual query.

user image

11:58 AM

@Isomorphic that chair question is a somewhat silly one and doesn't deserve all the vote is got, just as my answer to it doesn't deserve those votes either. You have the Hot Network Questions list to blame for that.

But I don't see how that's relevant to your argument.

user116211

@JohnRennie yeh, like the other day Newton's Third law got ;P

Your point seems to be that we should answer the questions you think should be answered.

math.uconn.edu/~kconrad/blurbs/grouptheory/SL%282,R%29.pdf

But the site as a whole has decided what questions it will and won't answer.

> Corollary 2.1. As a topological space, SL2(R) is homeomorphic to the inside of a solid
torus.

11:59 AM

You did not say "interior"

@ACuriousMind This is the PDF you linked me when I asked about this torus thing two semesters ago

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Transcript for

Jun '1624

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