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12:00 AM
Yep, right now it seems to be right around that value. We're in a bit of a summer lull though. Earlier this year it was more like 250/week.
It's pretty well correlated with a typical academic schedule.
The ratio is more constant though: we close 40-50% of all questions posted. If I'm reading my tools correctly.
 
That's...high
Higher than I would expect even though I feel there's a lot of bad questions being posted
 
Yeah... it would be nice if we could do something about that. If we think our standards for closing are too harsh, we can, but I don't think that's a major issue, in the sense that recalibrating our standards to a point where they seem right (to me, and to many other high-rep users, I think) probably wouldn't reduce that closure percentage by much.
I'm not sure if these numbers take reopening into account.
 
@DavidZ I think it might help if we tell the OP what to do. Doesn't hurt to leave a comment.
I realize that takes effort though.
 
I don't think we can do much about that - closing as a deterrent to ask further crap only works in some cases, and has no effect on new users at all, unless they've lurked
 
@ACuriousMind Huh?
Closing has no effect on new users?
Oh maybe I know what you mean.
 
12:07 AM
@DanielSank That...might be badly phrased
I mean that closing questions now doesn't do anything to deter a new user tomorrow from asking the same question
 
@ACuriousMind Closing a question from user A now doesn't deter new user B from asking the same question tomorrow.
^ That?
 
Yes, that
And a large part of the closeworthy question do come from new users
 
@ACuriousMind Right.
 
So I don't see anything to reduce that rate
The only thing we have some influence on is one the users that have already been here for a while
 
I can't speak for others, but I learned to use this site by participating in several ways. Seeing what other questions were closed helped a lot.
Reading the close reasons helped too.
 
12:10 AM
@DanielSank I lurked for like two weeks before I participated. Then again I do that in most online places...
 
@ACuriousMind I dunno. When you pull up to our site you see a bunch of closed questions. It doesn't take too long to get a feel for why they're closed.
::shrugs::
I'm just speculating now though.
 
@DanielSank Never underestimate how bad people are at inference.
In particular when you expect them to develop an understanding for what most users apparently see as a "hostile action"
 
@ACuriousMind Yes some users claim hostility.
However, given that I don't know what the homework policy says, what is the probability that relatively new users do too?
I speculate that people are less likely to perceive hostility if the rules make sense.
 
I agree
 
If I can reason that my question is closed for objective qualities, then I may not just fall back on assuming it's a random attack on me.
 
12:16 AM
However, what I find a bit weird is that you are the first person who really brought to my attention that the current wording of the homework policy doesn't make sense
 
I don't even link n00bs to the homework policy anymore. Instead, I explain what's wrong with an explicit comment. I figure that's more likely to make a happy n00b.
@ACuriousMind Yes, well, I speculate further that most users around here never thought about it and just click "close" when they know they don't like a question but can't figure out why or don't see a reason explaining their feeling.
 
Maybe it would be helpful if you compile your past comments of that sort, and we can see if we can extract any trends from them
 
@DavidZ oooof. Is there a way to do that easily (i.e. without me spending a ton of time)?
Actually screw it. I'm willing to spend time.
Sorry for sounding lame.
 
If this was the problem of new users, wouldn't some of them already have that pointed out to me? But no, all I get is "This is not homework?!?!" or "Why is my question closed an #randomotherquestion not?" or "Fuck you!" - or users saying they understand and will try to comply with the policy.
I can't recall a single instance in which a user would have said to me "This policy doesn't make sense!"
 
@ACuriousMind Yeah, they say "this is not homework" because the stupid homework policy says that a question being homework matters. Which it doesn't.
 
12:18 AM
@DanielSank I guess you could start with your comment activity from your profile
 
@ACuriousMind Why would they? They get to "homework" and immediately think the policy doesn't apply to them.
@DavidZ Oh. Why looky there!
 
@DanielSank might be...
 
@ACuriousMind Oh come on.
It's called the "homework" policy.
Go read the close reason, the help center, and the meta post.
The meta post is where it gets really bad.
Better yet, just read my meta post about this issue where I go through all the inconsistency and confusion.
 
@DanielSank I agree with that. I'm just not sure that most users ever actually read that post.
I do see your general point
 
@ACuriousMind I don't blame them at all. It's called the "homework" policy.
If they're not posting homework why would they go any further before protesting?
 
12:24 AM
And I do think it is worth fixing
 
If you get arrested for the "being a banana" policy, what's your first objection?
Do you go read the law?
Do you ponder the morals of arresting people for being bananas?
No, you say "look here, I'm not a banana!"
The fact that this policy is still called the "homework" policy is like 90% of the problem, I think.
We could call it almost anything else and I think this problem is mostly fixed.
 
@DanielSank The tag says "homework-and-exercises" and the close reason says "homework-like".
 
@ACuriousMind Dude, ok I arrest you for being "banana-like"...
 
Renaming it will fix the "But it's not homework!" reply, sure
 
@ACuriousMind It also means people get farther into the documentation.
Here's a good analogy.
Sloths are slow and lazy, right?
Suppose now you're drunk in public and I arrest you on the "sloth-like" law.
See?
 
12:27 AM
They're also vicious up close
 
@ACuriousMind :D
 
You don't need to convince me that renaming the policy is something that should be done. I'm just not convinced it's the major issue that needs fixing.
 
@DavidZ Is there a way to dump those comments? I don't wanna click through 117 pages of them :)
 
But we can't know that until we've actually fixed it, I guess
 
@ACuriousMind I think it's the biggest problem we have at the moment.
 
12:28 AM
@DanielSank I got that ;)
 
I think it fuels a lot of dissatisfaction in newish users who then don't turn into awesome users later.
 
@DanielSank SEDE maybe?
 
@DavidZ ?
 
The data explorer
data.stackexchange.com
 
@DavidZ Oh!
Awesome, I get to relearn SQL... again.
Man, that was exhausting. Anyone wanna talk about something fun?
Rogue One trailer!
Star Wars! Woooo!
 
12:34 AM
Didn't see it
But I don't watch many trailers, anyway
 
It's on Youtube. Interestingly, the European version gives up one more spoiler than does the US version.
 
I just watch whatever movies my friends drag me to :D
 
In general I like the trailer because it doesn't give up too much.
And the main character looks good.
I predict it to be better than TFA.
We'll see.
 
Well, I hope it has a somewhat original story, I'm not sure I'd like another rehash, although the last wasn't bad ;P
 
@ACuriousMind Indeed. As much as I liked the protagonists in TFA, I thought the story was surprisingly... unoriginal.
 
12:39 AM
Yeah, it was a bit surprising
 
JJ Abrams, dude.
He also re-used the Kahn story in Star Trek.
 
Although after one has watched/read hundreds of stories, finding a truly original one becomes rare anyway. I've begun to appreciate a well-executed story over an orginal one more the more I've read/watched.
 
It's funny how he keeps making crap and every keeps being surprised because Hollywood keeps saying "JJ Abrams = great!".
@ACuriousMind Yes well, "well executed" isn't exactly how I'd classify TFA, but that's another discussion.
 
@DanielSank I feel there's a diffuse but important difference between the SW and ST reboots, though: The SW reboot felt like a Star Wars movie, while the ST reboot fails to feel like Trek to me.
 
@ACuriousMind Sure. I agree. However, I don't see that as necessarily implying that the Star Trek movie was bad.
In fact, the first one was fine, IMHO.
Even though it didn't feel Stark Treky.
The second one though... yuk.
 
12:43 AM
@DanielSank No, it was...a nice action movie, I guess. But it wasn't Trek, and when I go watch something that's labeled as Trek, I want Trek
Even if that means watching Voyager :P
 
Fine. That's sort of orthogonal from the fact that Abrams keeps rehashing stories and making crap.
Right?
 
Yeah, it is
 
...quadratic equation shows up in linear algebra problem. What do?
The perfect nexus of things I'm bad at
 
The crap keeps selling, though
 
@ACuriousMind I guess.
I dunno.
I suppose Hollywood wants a guaranteed 80% instead of a risky 95%.
Revision: guaranteed 70%
 
12:48 AM
I seriously just used the quadratic equation to solve $\lambda^2-2a\lambda=0$.
:/
 
Yay, I'm now faced with removing 180 words from my paper.
 
Remove the first word of each sentence. That will at least make the paper "less obvious" :D
 
WAHAHAHA
Amazing.
 
 
3 hours later…
4:17 AM
@DanielSank I'd say I'm towards the liberal end of the spectrum as regards homework. I will usually answer if I think the OP will be genuinely helped by it. After all I have a gold badge for the homework tag!
 
4:44 AM
@JohnRennie I meant that given your fervor for pedagogy I would have thought you more interested in improving the documentation surrounding the homework policy.
 
@DanielSank The trouble is that the homework policy exists so that certain site members don't get fed up and leave. Documenting that is going to be a delicate process. Basically the reason for closing is we don't like your question.
I'm not saying that's a good thing or a bad thing - I'm saying that's the way it is.
 
5:11 AM
Yes that's all well and good. So why aren't you interested in improving the situation?
I'm just surprised.
 
@DanielSank After the conversation petered out yesterday I gave some thought to rewriting the homework policy meta answer, and I'll probably give it a try. What I usually do is write then immediately delete the answer so high rep users can preview it before it goes live.
 
@JohnRennie That's an interesting idea.
 
But it's going to be a tricky bit of writing as it's going to require some finely judged diplomacy.
 
@JohnRennie What do you find unsatisfactory about my previous meta post on this topic?
 
Hang on, let me find the link again ...
 
5:16 AM
25
Q: Should we rename the homework policy?

DanielSankThe homework policy is a constant source of confusion for new (and sometimes established) users. We see this confusion, for example, when users respond to closures based on the homework policy by defending their post with "This is not a homework problem", or similar. Some users have even been con...

@JohnRennie I think a new meta post is unnecessary when you could just post an answer to the existing one and we can keep the number of meta posts to a minimum.
 
@DanielSank Yes, I was going to add an answer not write a new post. If I write a new post it will only make everyone give oh no not again! type groans :-)
 
@JohnRennie hah, right.
 
@JohnRennie But... but... we need to stop using the word "homework".
 
I don't think your post gets to the heart of the matter. The key criteria are:
1. we don't want the main users to leave
2. we don't want the site to get a bad rep as a cheaters site
 
5:20 AM
@JohnRennie What happened to
3. New users need to not get confused/pissed off so that this site can survive and fulfill its purpose?
 
For diplomatic reasons I'd carry on using the work homework
 
Nobody cares about #3 and this is baffling.
I'm particularly puzzled by you omitting #3.
@JohnRennie I flat out refuse.
 
@DanielSank because the potential new contributors aren't going to find their questions closed very often.
 
Homework is not the issue, even if a lot of the questions which violate the rule we're trying to specify are from homework.
@JohnRennie eh?
 
I see enthusiastic youngsters joining the site from time to time, and you can spot them a mile off. Heather and Noah are two good examples. That type of user doesn't ask homework questions.
 
5:22 AM
Yeah, and Heather does a lot of stuff I strongly disagree with.
 
Because you're (relatively :-) old and worldly wise while Heather is inexperienced and enthusiastic. Evewryone gets old and cynical, but lets not hurry the process along :-)
 
I'm not sure what that's supposed to mean.
 
When I was 18 I was absolutely convinced that every cool idea I'd ever read in a SciFi book could be done and the old guard of physicists were just to stupid to realise it.
Now I'm part of the old guard I no longer think that way, but the universe is less exciting as a result. Still exciting, but no wormholes or transdimensional drives? Crap!
 
What does that have to do with having policies that guide users to use the site effectively?
 
5:28 AM
@JohnRennie Also, I'll just mention that this mentality is a little pet peeve of mine. I find a more disciplined understanding of the universe liberating. As a child my mind would wander aimlessly through all kinds of un-realizable stuff. It was frustrating to never be able to make any progress.
As an adult, I have more of a capacity to actually take an idea and do something with it
I find the notion of "young naive bliss" rather distasteful, in my own world view.
Not a criticism of you personally, but a point of view I like to share as I hope it makes other adults feel better about themselves.
@JohnRennie Yes fine, whatever. That's entirely beside the point that crappily written policies help nobody.
I'm very surprised that, given your stated interest in this site helping people, you don't care for the policy to be better. At least, you didn't earlier, but now you say you'll take a stab at rewriting the homework policy...
 
Let me go away and have a think, and I'll see if I can come up with anything coherent as a new answer for that homework policy answer. However it isn't going to be done quickly as I have a lot of work on at the moment.
 
@JohnRennie No problem.
 
 
1 hour later…
6:37 AM
@DanielSank I love SO(3,1) as much as the next physics student, but you have to admit it's very hard to convince a science fiction author that not having FTL drives is more interesting than having them
 
user116211
7:25 AM
Kyle's dp is famous ;P
 
7:37 AM
@0celo7 I can compute this 2x faster if all the projection operators are expressed in matrix form
 
7:50 AM
@0celo7 Suppose you have the matrix $A$. Then you should be able to solve the eigenvalue equation for $\lambda$ by finding $det(A-\lambda I)=0$ (which for 2x2 matrix you get a quaadratic equartion and thus you can in generally solve it by factorising or quadratic formula). After you get the eigenvalues, plug the $\lambda$ back into the $A-\lambda I$ matrix and solve for its kernal for the eigenvectors
@JohnRennie @NeuroFuzzy I still not very satisfied for the no progress (nor even concrete ruling out of) wormholes, transdimensional drives, backward time travel and FTL propulsion. However back in undergrad I do find the feeling of liberation as described by daniel e.g. knowing what entropy really is have caused me to understand the second law better as if I have finally resolved most resentment with a person I knew a long time ago, and find that the real life thing (instead of the popsci notion of entropy as disorder) is actually more interesting
I find it quite interesting that downvotes are positively correlated to effort. Shouldn't logically it should be anticorrelated instead?

Asking others whether it is correct is positively correlated with downvotes might be a reflection of what daniel and other said that we don't like askers who ask us to do the work for them

The ask for a detailed calculation being positively correlted suggest a similar reason above

It is also interesting how the conceptualness of a questiono is anticorrelated to downvotes. I am not sure how to interpret that
Check my work, interestingly also postively correlated to upvotes. I wonder if these opposite correlations for similar aspects of questions is one reason why most questions have on average zero votes
 
 
1 hour later…
9:08 AM
Anyone around?
 
 
2 hours later…
10:55 AM
@NeuroFuzzy My personal opinion is that if you think the important thing in "Science Fiction" is science, then you're doing it wrong. The "science" in science fiction stories (except in the really "hard SciFi" ones) is not really different from the "magic" in fantasy novels: It's a plot device that enables the story being told, but it's not the point of the story.
 
2
Q: Harmonic motion of negative charge between two positive ones

Dovah-kingI have to prove that a negative charge will execute an harmonic motion when placed in the line that separates two positive charges $Q$. (The negative charge $-q$ will not be placed on the center). I clearly understand that it will be an harmonic motion, but i can't show it mathematically: i've tr...

This has been flagged for review - I want to see what other people think
Looking only at the question itself, of course: on topic or off topic? (according to our current policy, not whatever new one we might come up with)
 
@DavidZ No evidence of any significant effort on his part?
 
@NoahP Are you asking or saying?
 
Saying, tentatively
@DavidZ
 
So that means off topic, I presume.
 
11:00 AM
@DavidZ Well, I voted to close, and I haven't changed my opinion. That the problem is hard to solve doesn't make it any less of a homework-like question.
The user in the comments appears to be of the "I find this question interesting, so it is not off-topic" variety :P
 
Of course it's a homework-like question. That itself isn't reason to close.
Ignore the comments for now.
 
@DavidZ Well, it doesn't ask any conceptual question, and it shows little effort, so it passes neither of the two criteria we expect from homework-like questions to stay open.
 
Noted...
 
@DavidZ If there were evidence of effort on his part, and was asking more about the concept, rather than a 'how?' searching for a direct answer, then it would be less off-topic
 
In particular, it doesn't even formulate a specific question - it just says "Any help would be great", so the implied question is really just "How do I solve this?"
 
11:02 AM
But it doesn't appear to look that way
@ACuriousMind Exactly
 
It would be nice to get input from other close voters too. @knzhou @JohnRennie
@ACuriousMind Agreed. Now, that being said, a hypothetical: what if "Any help would be great. Thanks!" were removed?
 
@DavidZ I wasn't aware of the chat last night until about 15 minutes before, and didn't have the chance to participate - could you sum up what was decided on the homework policy?
 
We decided that we suck at making decisions about the homework policy ;-)
 
@DavidZ Well, then the question would be implied by "The problem is that im not being able to change this equation in order to get the traditional simple harmonic motion differential equation.", right?
 
@DavidZ Ah, right. And as such have decided not to make another?
 
11:05 AM
@ACuriousMind Yeah, I would say so.
 
Which, again, just asks us for how to derive one equation from another. It's not clear from the question that there's any conceptual hurdle here
 
@NoahP Why would you say that?
 
Without trying to actually solve the problem, I can't judge whether OP is just incapable of basic mathematics or whether this is a problem worth looking in more detail at
 
@DavidZ Well it was a stab in the dark, I took your reply to mean you didnt actually decide anything
 
That's not a good question - asking a conceptual question means in particular that I can tell a question is conceptual without actually trying to answer it
 
11:07 AM
@NoahP Indeed, that is what it means. Things are rarely decided in chat anyway.
Basically, many people are dissatisfied with the current policy but there is major disagreement about what to replace it with.
 
Yeah, I think it could definitely do with tweaking
My main observation is that it seems to be applied with little discretion
 
@ACuriousMind We do have a meta post saying that mathematical questions in the context of physics are on topic, and I think this is the sort of thing it was meant to apply to.
@NoahP yeah, that's the main motivation for replacing it.
Granted, it's not but it's kind of de-facto policy AFAIK, and it is in the help center.
 
@DavidZ Some genuinely interesting questions tend to get marked off-topic
 
@DavidZ Okay, let me offer a counter-hypothetical: What if the question only had one force $F_1 = kx$, so it would effectively be asking us "How do I derive simple harmonic motion from $kx = m\ddot{x}$?". Would that be on-topic?
I do think that "mathematical questions in the context of physics" are okay, but not "Solve this equation for me"
 
@ACuriousMind If sufficient prior research was done, sure (IMO). That being said, it's unlikely that someone would be able to do sufficient prior research on that question and not find the answer.
 
11:15 AM
Meh, I still don't think that "Solve this equation for me" would be on-topic, since the answer is potentially "There's no analytic solution, just feed it to your favourite numerical solver".
There's neither physical nor mathematical insight in the generic process of solving an equation
 
That's a valid answer, I think.
In my opinion, the situation where someone struggles to solve an equation that is not analytically solvable should be a valid topic for a question on this site (given that we say math in the context of physics is on topic). And in that case, the answer would be that there is no analytical solution, so you should do it numerically.
 
Yeah, I don't agree with that. If the question is really just how to solve the equation, then it gains nothing from the physical context, and can just as well be asked on Mathematics. Physicists neither have idiosyncratic diction nor special techniques unknown to mathematicians when it comes to solving equations, as far as I know.
 
@ACuriousMind If the maths stack exchange catches the tiniest whiff of physics, they'll send you packing - speaking from personal experience.
 
I'll admit I may be biased here because I generally find the task of solving equations boring and never understood why people think any particular equation is "interesting" :P
 
@ACuriousMind Sure, and I think if you disagree with the whole idea that mathematical questions (in the context of physics) should be on topic here, that's a reasonable position to take.
@ACuriousMind Well, I don't know that anyone who thinks such questions should be on topic does so because they think it's interesting. I think they should be on topic (if we are admitting mathematical questions) because it's useful.
 
11:22 AM
@DavidZ No, no, no, I don't think a mathematical question in the context of physics should be off-topic. I think that solving an equation actually isn't a question "in the context of physics" - you can strip away all the physics and the question is still the same.
 
I mean, we shouldn't be using interest as a criterion to decide what is on topic or not, as much as we can help it, right? ;-)
@ACuriousMind That's exactly what I mean by "mathematical question in the context of physics"
 
@DavidZ But what happens when you get a genuinely interesting question that could result in alot of discussion, but violates a policy?
 
@DavidZ Then we have different ideas of what we're talking about, I'm afraid
 
@ACuriousMind Well, whatever you call it, we have that meta post which is about that type of question. The community seems to strongly favor keeping such questions on topic.
@NoahP Close it, of course. That's easy.
 
To me, a mathematical question "in the context of physics" is asked embedded in a physical narrative such that it is a priori not exactly clear whether the answer is pure mathematics or aided by physical reasoning
 
11:25 AM
@DavidZ I think that's a shame, shouldn't the site aim to encourage discussion and engagement?
 
@ACuriousMind I would call that a physics question. But again, we shouldn't get hung up on the terminology.
@NoahP No, the entire point of Stack Exchange is good questions and good answers, without discussion to distract from them.
 
@DavidZ Well, but it is kind of relevant in this case because you keep telling me that my position is "against mathematical questions in the context of physics" ;P
 
Besides having a chain of reasoning involving physical concepts, a constraint or condition that stems from considering the physical aspect of the problem to be added to the equations, what are the other examples of "physical reasoning"?
 
The meta post seems to favour your interpretation, but "motivated by physics" is a rather ridiculous criterion for on- or off-topicness, as @DanielSank's comment about 1+1 aptly demonstrates
 
@ACuriousMind Yeah, but now that I realize you're not using the term the same way I am, I'm saying forget about the terminology. Your position is against <X>, and we have a meta post showing that the community thinks <X> is on topic.
 
11:28 AM
@DavidZ Ah. If there were a capacity for discussion about concepts that are slighty less mainstream, would that not be beneficial to the number of people who used the site, thus having a knock on effect on better questions and answers?
 
@ACuriousMind That I disagree with. It's not the criterion I would personally use, but it's not ridiculous.
 
@DavidZ With your reading of this policy, a lot of the questions being closed as homework are actually on-topic.
I have a feeling that this answer was written with "advanced" mathematics in mind and most people did not stop to consider what it does when applied to "elementary" math.
 
@NoahP There is, we have chat. That being said, I don't think those discussions would necessarily benefit the site anyway.
@ACuriousMind That certainly could be true.
 
@DavidZ Fair enough
 
However, with your reading of the policy, I would have to say the question we're talking about is on-topic by this policy, but still off-topic by the homework policy.
 
11:30 AM
@ACuriousMind I wouldn't say that. I would say that a lot of the questions being closed as homework-like don't hit that particular restriction. But that's not why they're being closed.
 
The question is now which policy takes precedence.
 
@ACuriousMind Yep.
 
@NoahP Discussing non-mainstream things would certainly be beneficial to certain users, but it is not a direction I want this site to go into.
 
@ACuriousMind There's not really an issue of precedence. In order for a question to be on topic, it has to comply with all policies. If one policy says it would be on topic but another one says it would be off topic, it's off topic.
 
@ACuriousMind Perhaps a chat room specifically for this? Surely some sort of compromise is there?
 
11:33 AM
@NoahP If you want to talk with someone in chat, you can just open a new chat room and invite them.
There's no content policy for chat, it's already "talk about whatever you want to talk about"
 
@ACuriousMind Would that function like the h-bar so that people can come and go at will?
 
@NoahP Sure
I wouldn't come, but sure
 
Okay, I didn't realise that
 
@DavidZ Yeah, okay
 
One thing to be aware of is that chat rooms get frozen if nobody uses them for two weeks (I think), except the main chat room for each site.
 
11:35 AM
@DavidZ Okay
 
Well, I'd say that if your chat room gets frozen regularly, you may not have actually enough interest in it to keep it going :P
 
Yeah, that's the idea
 
I might create one as an experiment?
Just to see the interest in it
 
Sure... I mean, the chat system is designed so that creating new rooms is easy and there's no real "cost" to it (except perhaps fragmenting a conversation).
 
12:06 PM
I had a nightmare about GR
Welp, it's right
 
12:19 PM
@JohnRennie
"relativistic increase in mass"
 
@0celo7 @ACuriousMind

Spherical coordinates:
\begin{align}
& \hat{x}=\sin \theta \cos \phi \hat{r} + \cos \theta \cos \phi \hat{\theta} - \sin \phi \hat{\phi}\\
& \hat{y}=\sin \theta \sin \phi \hat{r} + \cos \theta \sin \phi \hat{\theta} + \cos \phi \hat{\phi}\\
& \hat{x}=\cos \theta \hat{r} - \sin \phi \hat{\theta}
\end{align}

Hence

$$\begin{pmatrix}\hat{x} \\ \hat{y} \\ \hat{z}\end{pmatrix}=\begin{pmatrix}\sin\theta \cos\phi & \cos\theta \cos \phi & -\sin\phi \\ \sin\theta \sin\phi & \cos\theta \sin \phi & \cos\phi \\ \cos\theta & -\sin\theta & 0 \end{pmatrix}\begin{pmatrix}\hat{r} \
 
please no
no don't write it like that
 
what is the correct way to convert a V from xyz basis to rthetaphi basis?
 
use the tensor transformation laws
 
@0celo7 A nightmare about doing GR or a nightmare like "falling into a black hole"?
 
12:24 PM
so only work with the components?
 
@Secret That's not a good way to write things because your "matrix" in the middle is not independent of the vector on the right.
 
@ACuriousMind I realized the usual existence proof of convex normal neighborhoods in Riemannian geometry fails miserably in Lorentzian geometry.
Currently going through a crisis.
 
That is, you're not doing a simple linear transformation here, so don't act as if you do.
@0celo7 lol
 
How is it funny?
 
Did you realize that in a dream?
 
12:26 PM
Yes.
 
Well, that is funny
Although the fact of the matter sucks for you, obviously
 
I was defending my bachelor's thesis
dunno if that's a thing
And I said "cf. do Carmo" for the proof of existence
 
I think I need to reread my linear algebra notes on how to convert a vector from one basis to another properly a bit later
 
and then one faceless prof said but geodesic balls do not work on Lorentzian manifolds
and I woke up
 
I am always bad at things that happens all at once
 
12:28 PM
If there's math in my dreams, it usually is just gibberish
I tend to dream strange stories taking place where I grew up
 
@0celo7 That faceless prof. was your conciousness o_0
 
@ACuriousMind I've dreamt multiple times that I proved one cannot integrate over compact sets
 
@ACuriousMind Mine was a bit mixed. I have maths from my dreams that turns out to make sense
 
@ACuriousMind I get some good ideas in my sleep
 
but nothing really radical, of course
 
12:29 PM
@0celo7 Are you sure those are dreams, and not your thoughts shortly before falling asleep/after waking up?
 
@ACuriousMind No, because one can integrate over compact sets
 
@0celo7 Well, sure, but the sleepy brain is a stupid brain
 
I've also had a nightmare about V.I. Arnold
I was trying to get my PhD under him, and the final test was to do an integral
it was some horrible elliptic integral
anyway, if you failed the test, you got shot (true Russian style)
I got shot!
 
0celo7 if you can remember the detials of your dream, I might be interested in reading about your dream proofs. I think it might inspired me something that otherwsie my waking life have struggle to conceive
 
@Secret I have very vivid dreams
 
12:31 PM
so do I, I have 5 years of dreams logged in
 
@0celo7 lol
Your dreams sound way funnier than mine
 
crisis deepens
 
For example, 2 nights ago, I saw a standard model that looks like this
 
How do you prove manifolds are connected by broken geodesics o.o
that can't be too hard
No morse theory allowed
@ACuriousMind Do you see a Morse theoretic proof?
Glorious. Lee contains a full proof of the convex normal neighborhood thing.
 
It's really never math or physics for me. In the last dream I remember I was living in a large house with about a dozen friends and we were...defending it against some sort of attackers. I never saw them, but they picked off my friends one after the other. I woke up after running with a raised axe towards the door.
@0celo7 I don't know what "connected by broken geodesics" means.
 
12:36 PM
@ACuriousMind $p,q$ in $M$ can be connected by a broken geodesic.
The claim is that this is possible iff $M$ is connected topologically.
But there must be an elementary proof.
 
My dream last night is more like being in a movie. There's a house that me and a group moved in. Later on in another cutscene, there's a woman who was haertbroken thus she stab herself, then went to a window to inhale some greenish gas, and then she transformed into a witch or something. Moving back to the house scene, a female caretaker revealed all the secret passages of the house and told us (we are all kids) that this is actually a secret bunker for training kids with special powers
 
@Secret Cool fantasy.
 
These movie dreams are pretty cool. Sometimes they can occur in layers (i.e. dream within a dream)

My highest record of dream layers is 5 layers
and not suprisingly on that day I am kinda disoriented
 
Inception
 
speaking about inception, my dreams do started to get complicated after watching that movie
 
12:42 PM
@ACuriousMind I...I think the proof will just use Picardy.
 
The current degree of complexity is that each my dreams has its own history, and everyone including me has a different memory as if we had lived a comepltely different life.
 
@Secret stop the drugs
 
I have not touched any drugs, lol
unless cyclosporine have such weird side effects
Below is an example of a EM related dream that is detailed enough I end up asking my professor about it
 
@Secret Well I bet you can use this thing as an advantage for yourself. Become a screenwriter, director, or whatever.
 
Well I already taking advantage of that. Some of my weird questions that lead me to learn new maths from reading text etc. are actually triggered by seeing weird maths in my dreams
For example, that above dream have generated a question shown above that lead to a better physical intuition of me in checking whether a formula makes sense
 
12:53 PM
@Secret You know, I told you once this chat isn't a diary. Seeing that you write exactly in the same way when you write for yourself as you write in this chat makes me think you haven't really understood that.
Communication takes effort. Communicating your ideas to other people is different and harder than just preserving them for yourself.
 
Since you guys have been talking about dreams, I want to share mine also, but I am not sure how in terms of parts of speech I should use to share them
 
@Secret My point isn't that you shared your dream. My point is that that screenshot there could very well be something that you posted directly to this chat, in that exact phrasing and with those line breaks
You've often asked why I say you're hard to understand
I think this is the reason: You don't actually try to write such that other people can understand you. You have no "private mode" and "communication mode", you just write the same way regardless of the intended audience.
 
@ACuriousMind @Secret BTW, is it poetry and writing community? I think the chat room has changed its working strategy?
 
If I showed you notes I make for myself, you wouldn't be able to make much sense of them either, I guarantee that. But I don't write in that stream-of-consciousness, disjointed way when talking to others.
 

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