12:01 AM
@0celo7 what do those acronyms stand for?

@StanShunpike Look up Briggs-Meyers personality test.

Ah, that thing. I know about that. I was like an uber extrovert
Is this ur AP psych class? My bro is a psych major.

Yeah

12:32 AM
@0celo7 Myers-Briggs is total BS
that's the physicist in me scoffing at the social "sciences"

@Sean True, but Minnesota costs money.

1:03 AM
@0celo7 I've taken it a few times & got ENTJ twice and INTJ once. So I'm not really sure how intro/extro-verted I am, but I do seem to be Intuitive, Thinking & Judging

@KyleKanos Really? I took you for something counterintuitive

Psychology is a fun subject :-)
A great mix of applied biology and philosophy.
No need to scoff @Sean ;-(

1:28 AM
@NeuroFuzzy Hmm, well the internet can do that, I think.

How can we do integrals on a manifold? I am reading Bernard Schutz's book on GR and he talks about doing this.
I just don't get how we know we can do integrals on a manifold. Given all the complexities with differentiating on a manifold, why can we integrate like this along one of the coordinate lines?

1:48 AM
@Sean Which they sometimes deserve no doubt, but I thought even psychology understood that Myers-Briggs with BS.
It's just something AP psych teachers love, because it involves a worldview that's simple and easy to grasp, yet just complicated enough to make it seem worth studying.

@ChrisWhite My teacher admits that Myers-Briggs is too simplistic. We learn about the Minnesota test, which has ~500 questions and is constantly tweaked, but it costs money so we can't feasibly take it.

Free is good :-)

@StanShunpike Well, the simple answer is forget there's a manifold at all, since your coordinate chart means you can consider yourself to be on $\mathbb{R}^n$

The better answer -- Carroll covers this -- is to really understand what each symbol means

1:52 AM
Stole the words from my fingertips

for example, the d is the exterior derivative, the final x^1 is a scalar function on the manifold, dx^1 is therefore a 1-form, etc.

How do I make a landscape Word doc?

@0celo7 Use latex :P

@ChrisWhite I need pictures tho
Also I figured it out

Honestly, I have no idea. Ever since Office changed from menu-based to picture-based navigation, I've never been able to find any features.

1:55 AM
@0celo7 Click the orientation button

@KyleKanos I looked everywhere but that place
Then I asked and found it immediately

@0celo7 You didn't check with MS Office support? Why?

@0celo7 What I really want to take some day is one of the psych tests administered for people in sensitive positions -- the kind that are supposed to stress you out and see if you hold up.

I know someone who interviewed for the NSA once, and they gave something like that clearly designed to catch you in a lie.

1:57 AM
@ChrisWhite Coming from a family rooted in government service, all clearances work that way.
In the military they ask you if you have performed or have received oral sex.
It's against the UCMJ to do so.

@infinitesimalsimplicio Sodomy is also illegal in the military, obviously. Although that might be changing.

Talk about out of context >8(
You go in the military to kill people. Nothing else.

I hope you're kidding.

Have you seen Stripes?

2:01 AM
During war.
No @StanShunpike

@infinitesimalsimplicio Yeah, I'm gonna have to go ahead and, uh, disagree with you here.

I meant during war only

Even during war, that's not true
You're talking about one specific subset of "military"

Exactly

There's a bigger superset that is involved in not killing people

2:04 AM
True

And not everyone joins the military to legally kill people
They do it for other reason (money, for one)

But they just provide support

That depends on your definition of "support"

Bullets

That...does not compute

2:05 AM
Do people die in war?

Usually, yes.

I know that bullets kill people, but I asked for your definition of "support." You responded with bullets

Providing bullets

The clarification of that word was in response to your statement that people provide support by joining the military
Do you even know how the military functions?
Like any siblings or close relatives in the military?

2:08 AM
Yes.
Most died in action.

Perhaps you should ask the survivors how the military functions

@KyleKanos You a vet?

They don't care about "function " only the loss

@0celo7 No, but I've got 2 brothers in the military, one who served for 6 years, and several cousins both active and served
Plus a few uncles, most of whom went to Vietnam

@KyleKanos My father served in Vietnam.
My parents and godparents served. By extension, virtually all close family friends are military or former.

2:11 AM
My father was in the military during Nam, but his duties involved training helicopter pilots State-side, so he did not go over with his brother (who flew helicopters over there)

I didn't mean to offend your military background. @KyleKanos
I still feel the loss.

2 hours later…
4:33 AM
Are flags reviewed just by moderators or by any community members with enough points?

Yep, +10ker's
for chat flags
iirc :-)

@StanShunpike some flags are only reviewed by mods, but I forget which ones
Certainly at least custom flags for moderator attention

Are there custom chat flags for mods only @DavidZ?

I think so, but again I'm not sure. Actually I never handle chat flags.
Y'all are too well behaved :-P

4:46 AM
^^amusing
from my friend in Penn State's SPS

But is it really always a wise thing to say?

I guess "clever" is not necessarily the same thing as "wise"
but I'm sure there's some proverb about that

I'm not so sure about the "clever" part either.
So according to that, during our interactions with people we should spend most of our time doing nothing, right?

Yeah, but I bet a lot of people would benefit from moving closer to saying nothing than moving away from it

True.
If you factor in body language it makes more sense, I think.

5:12 AM
Is there a way to use tensor products to describe the Riemann curvature tensor? Just curious.

6:12 AM
You can definitely express it as a linear combination of tensor products of lower-rank tensors, but that's true of all tensors
If you're asking whether the curvature tensor can itself be expressed as a tensor product of other tensors (or other meaningful tensors), that I'm not sure about. But I'd guess no.

1 hour later…
7:17 AM

4 hours later…
11:33 AM

Lol, an old question of mine just randomly got downvoted (?)
That has never happened to me before. Late upvotes are more common :P
@infinitesimalsimplicio ?? lol
@0celo7 Yes, a little bit! My course on diffgeo actually focused a bit on this---using Frobenius' theorem
@0celo7 Take the differential at the identity, I'm pretty sure.
@StanShunpike Its the point of the notation that is packs a lot into a small space
@StanShunpike Any law in tensor form is true in all coordinate systems---that's one of the most important motivations

12:14 PM
@Danu I came up with the same program myself, so I think that is correct and makes sense to me.

12:31 PM
@Danu Do you know what the standard basis for sl(2,C) is? I first thought the Pauli matrices, but the algebra is 6-dimensional.
@Danu Perhaps the Pauli matrices and then i times the Pauli matrices...although they are not linearly independent.
Ah, I recall from previous studies of the Lorentz group that this is correct, with a factor of 1/2 in front of everything.

12:54 PM

@Danu What's funny?

That I found it by googling "basis of sl 2 c"

@Danu I'm sure you know that sl(2,R) != sl(2,C).

Didn't look at the contents

1:24 PM
@0celo7 $L_+^\uparrow$ is some restricted Lorentz group? But, anyway, you obtain the algebra homomorphism as the derivative of the group homomorphism. In general, the adjoint group action $BAB^\dagger$ is $ba+ab^\dagger$ (for $a,b$ generators of $A,B$) infinitesimally, it has to do with some version of the BCH formula, I think.
@0celo7 Complexifying the algebra often makes things easier without significantly changing the rep theory, by the way.

I'm always amazed by questions that I figured nobody would look at and might get closed as off-topic and then they get me a ton of rep when I answer them

1:42 PM
@ACuriousMind Algebra homomorphism? Is it not guaranteed to be an isomorphism?

@0celo7 For such covering maps, it should be an isomorphism, yes. But that doesn't change that the algebra homomorphism is the derivative (or, more precise, "induced map on tangent spaces") of the group homomorphism in general, regardless of whether one of them is an isomorphism or not.

Cool, thanks.

2:25 PM
arXiv papers titled "Comments on..." or "Response to..." are always a fun read.

@ChrisWhite I asked a question last year about a long chain of arguments. At least one or two papers have come out this year (which I have not edited into the question). One of the authors of one of the papers answered the question.
I also have read parts of this debate which has been going on for years.
And then there are the more "direct" fights such as this and this

2 hours later…
5:05 PM
0

I'm working on a program that has to do with adding sound waves on top of sound waves. Currently what I'm doing is simply an average of the two waves. So if I have wave A, and I want to write wave B 'on top' of it, every sample in the new A is equal to the average of two matching samples in the o...

off topic?

@DavidZ Looks like it could be asking about superposition of sound waves

I'm leaning towards off-topic because, while it is kind of physicsy with adding waves, it's definitely in the realm of audio engineering and there's probably scores of people on another SE that deal with exactly this problem

I feel like ultimately the person wants to do audio engineering, but since the question is phrased in general, with no reference to file formats or software, I'm inclined to classify it as physics.

@DavidZ Argh you deleted that answer just before I managed to post my usual "-1, don't feed the bears!" comment
Spoil sport

0

` Where can I learn about the functionality of motors and generators, so I can answer questions such as these? I need a good textbook that starts from the basics (eg faradays) then moves up with lots of questions. Can I also know if this is hard to pick up?

also off topic, I think
@ChrisWhite well the first sentence is "I'm working on a program..."

5:16 PM
@ChrisWhite in physics, we can simply play the two sounds simultaneously. That will add them together and won't decrease the volume of any individual sound. This question has to be taken in context of combining sounds in a software program, otherwise it is so trivial that it doesn't make sense
@DavidZ EE.SE?

I don't think EE deals with motors
but maybe I'm wrong?

@Jimnosperm The question the user wants to solve doesn't look like EE at all to me

Looks like an electric motor. electrical engineering works with them

It's a resource request correct?

@ACuriousMind true. Fair point

5:18 PM
It doesn't matter, anyway. The question is whether it's on topic here or not. We don't need to think about whether it's on topic on some other site.
(until there appears to be a consensus that it is off topic here)

This is a not even wrong question
you don't need to know about motors and generators to answer the questions

The question asks where to find resources to solve the question. Seems on-topic in a sense to me, although I think anything about Newtonian mechanic will suffice, so I'd be a duplicate of the book recommendations

FWIW I think that if a question asking for books showing how to do X is on topic, it also implies the question that directly asks how to do X is also on topic. And vice versa.

@DavidZ I disagree. One asks "What can I use to learn/find out how to do [X]?" The other asks "Do [X] for me"

@Jimnosperm ^ I agree with that

5:27 PM
^I agree with agreeing with that

^ I agree with chaining agreement in this manner

Lololol

Stan! You should have written "^ I agree with that" and started an infinite loop

Someone had to break the monotony :D
Are resource requests off topic?
I have found chat responds better than the actual SE.

@StanShunpike No, though I and a couple others put up the good fight to make them off topic.

5:37 PM
Yeah some ppl clearly don't like them

@StanShunpike I'm also in the "No" camp, but you win some and you lose some.
The"Yes" people effectively promised to keep them curated and maintained to maximize their value and minimize the basic incompatibility with the SE system. As far as I can tell they're mostly keeping up with the work.

I'm firmly in the "Undecided" category. And given the amount that this problem affects me, that's not likely to change soon

^ Seconded

Oh man
I just got flagged over at History of Science and Mathematics for "welcoming" a user in a way that is standard on PSE. The flag says that I was being too rude :\

@Danu Yes, we are a bit rude here

5:53 PM
@Jimnosperm I dunno if I'd say rude... more just bitter and jaded :)

@tpg2114 To a non-bitter and non-jaded person, they sort of appear the same
@Danu Your comment wouldn't have been rude if it were properly addressing the question. But given that it didn't, I'd say that added a "rush to judge" quality that increased rudeness above normal levels

@Jimnosperm It was a genuine misunderstanding :\
I somehow failed to read it properly

I know, but other people interpreted it differently

I improved my second comment to reflect it more clearly

6:21 PM
why do the histories of maths and physics get lumped in together in one SE? they are sometimes related, but generally quite distinct, aren't they?
oops, i mean history of science and mathematics. now surely they are distinct? or not?

Well Newton invented calculus to do physics
So there's some intermingling of science & mathematics

They aren't as distinct as you'd think
Math may not be a natural science, but it's still very scientific. And where else would you put it?
History of Math and Culture?

I'd separate History of Math and History of Science - these subject have occasionally intertwined, but are generally detached

They aren't broad enough independently to be their own SE site
Okay, science may be, but math isn't

That's my naive feeling. I'm quite interested in the history of science and of maths, but I haven't read much about the latter

6:30 PM
-12

Proposal: History of Science and Mathematics Can we just go ahead and make this site a site for the history of academics, it is much more general and would attract more people to this site.

There was a request to make it more general, but it was firmly rejected

was there a request to make it more specific?

Not that I can see
It seems like it was always about Science & Math

They do go nicely together

@Jimnosperm: Uh, that was spam: hayneedle.com/patio-umbrella-buying-guide.cfm

0

I'd like to point on the idea of question as a knowledge resource. It has come to my knowledge that understanding a subject, especially Physics, requires experience with as many questions as possible. Reading many solutions of expert members of the Physics site may indeed help many students t...

6:34 PM
@KyleKanos what was spam?

Honestly, I didn't even look at the link. Either way it'd be deleted

Yep

@KyleKanos If we're critiquing each other's LQ reviews, might I call on this one
The answer explains waveguides but the question is about how electrons carry signals through a cable

7

The options for Low Quality posts are No comment needed Commentary on another post A "Thank you" comment "I'm having this problem too" comment Different question than posted Link-only answer (and not spam) "This is a bad answer" does not appear on the list, so voting to delete such an answer ...

6:42 PM
You are saying that it doesn't fit with any of the choices?

I do not think so, no

It does fit with No Comment Needed

That, in my opinion, is to be used when someone else has already put the canned-comment in

It's not an answer to the question. It's an answer to a totally different question
@KyleKanos If someone else already put the canned comment in, then choosing the appropriate reason only upvotes the comment, it doesn't repeat canned responses

@Jimnosperm I know. But the act of it is saying Someone else already told them why it's being deleted, I don't need to do so again

6:45 PM
I use No Comment when I add my own comment in. If I can explain why I think it's inappropriate as a posted answer to the question, then I write that comment and select no comment needed, because I provided one already

I think if you have to write a comment that is explaining yourself, "Looks okay" is the button you need to press

2

Depends. A downvote should be the solution in the case the post is not useful. As in: It is technically correct, but isn't clear. It is technically correct, but is only a link or is of some other value. It is technically incorrect, but is of some value to the original question. Deletion is r...

Sure, be selective
Skip out on the +10 accepted answer
9

If a question is flat-out wrong on top of being exceedingly brief, in poor English, or whatever, by all means vote to recommend deletion. If it looks beautiful except for being wrong, I'd stick with downvotes and comments.

> If it looks beautiful except for being wrong, I'd stick with downvotes and comments.

But it's not even wrong

If it does not answer the question, then I do not see how it is anything but wrong

6:48 PM
Q: What's the square root of 2? A: Bananas are yellow.

Downvote, comment that it doesn't answer the question, move on with life

That's not even wrong, it's just not really an answer
Not answering the question is grounds to flag it as not an answer

And I somewhat agree

@innisfree There is a big overlap (also in terms of expertise of users) and the audiences for each separately are probably too small to justify a site.

If an answer is (a) asking a new question, (b) meant to be a comment on another post, (c) a thank you comment, (d) a "me too!" post or (e) a link only; then by all means flag it as not an answer

6:54 PM
@innisfree There's a lot for you to discover, then!

If the answer is just flat out wrong, then downvotes & comments as to why it's wrong are the necessary action

20

A bad or a wrong answer is still technically an answer. Moderators aren't here to judge the correctness of answers. That's what the voting system is for, so the right way to handle those is to downvote, edit, or leave a comment. The "not an answer" flag is for posts that are either completely un...

6

Other than off topic flags, there are several different types of flags that one can cast on a question, answer, or comment. What are each of these flags for? Question and answer flags: spam offensive/abusive/hate speech not an answer very low quality other Comment flags: rude or offensive ...

> Do not use this flag for anything that answers the question or represents a good-faith attempt to answer the question, such as wrong answers
(where this flag is the "Not an Answer" flag)

It also says use it for answers to completely different questions
The first bullet point of when to use the flag

With the caveat answers which just barely fail to address the question due to an honest misunderstanding

6:57 PM
@innisfree I think you're wrong about this. There really is a ton of overlap (of course especially between physics and mathematics)

How do you know the poster of that answer didn't misunderstand?

Talking about how EM waves travel through a waveguide when asked about how electrons carry signals through a cable is sufficiently unrelated

That's obviously debatable.

@danu there's certainly overlap between maths and physics - as @kyle noted, occasionally revolutionary developments in maths were motivated by physics, and vice versa - but the overlap between the histories maths and e.g. biology is tenuous.

I've answered a few questions (and commented on more) based on my misreading the question

7:00 PM
and even with maths and physics, most developments in maths have nothing whatsoever to do with physics.

@KyleKanos What? Other than them both carrying information along something and being elements of the EM force, they're not related
And misreading is one thing but turning electrons into EM waves and cables into waveguides is something else

@innisfree I don't really agree on this point
The other point is fair enough... It just turns out that most people interested in either discipline turn out to have at least a mild interest in the other as well.

for a start, maths is arguably much older than physics

@Jimnosperm Yes, and if you gloss over the fact that it (clearly) says electrons, and read the "transmit " and "cable", you can think of waveguides

You'd also have to gloss over "electrostatics" and "twelve years old". Plus glossing over "electrons" is a pretty big oversight

7:04 PM
I concur

But that's neither here nor there. The answer is clearly only suited for a totally unrelated question

But I don't think it's not an answer

Is it an answer to the question. Even remotely?