@ACuriousMind And I'm a mathematician. We are always correct.

to this^ may I add physicists are the law makers

LOL :)

No you may not add.

God is the law maker, or whatever entity created the universe.

You merely observe God's laws, and, in this case, ignorance of the law really IS no defense :)

To know his thoughts?

Science observes and predicts. It's like a blind man in a cactus store.

Well, anyway, however the legal standing may be: Closing a question is not a legal procedure, and it is not a punishment. The intent is to get rid of questions we don't want to have here, not to punish the user.

@ACuriousMind It was @JohnRennie who made the analogy. We can return to the other debate now.

The entire question is: what sorts of questions don't "we" want to have, who is "we", and what makes them "we".

@MAFIA36790 Oh, not the Clausis-Clapyeron equation then.

@MAFIA36790 I don't know what that means but something like work done at a temperature can never be done again except at a lower temperature.

@barrycarter Ideally, "we" denotes a sizable fraction of the active users around here. I recently wrote a rather long meta answer reflecting on some aspects of what "the community" and "we" usually means in the context of closing questions

@ACuriousMind Right. My concern is that you're keeping a vast majority of potential new users out via these rules, so you're effectively creating a dictatorship. Simply based on all the homework questions we get, a lot more users would want to change the rules if you let them be more active by not closing their questions.

@ACuriousMind It's like saying "I believe in democracy... provided no new people come in who disagree with my opinions"

@barrycarter : IMHO you shouldn't be concerned about "keeping a vast majority of potential new users out". Physics Stack Exchange isn't intended for homework help. However what you should feel concerned about is just how many expert posters are ex posters.

@barrycarter Well, but those "potential new users" are not users we want. That people who are not currently active members of this community would want to change how this community works is completely irrelevant. To continue your crude political analogies: It's like saying the millions of people in a neighboring country bent on invading us should get a say in whether or not we open the borders for them.

@ACuriousMind Oh, I thought Physics was an open site. You're saying it's not?

@JohnDuffield But if this community is defined by its users, keeping users out violates the spirit of the community.

@barrycarter It's "open" in the sense that you can ask questions and answer them without any sort of hurdle - there's no "approval board" for new members or something. But it's certainly not "open" in the sense that you can do whatever you want here.

@ACuriousMind No, I mean that new people are not allowed into the democracy.

@MAFIA36790 But it's just us. No newbies allowed?

@ACuriousMind "millions of people in a neighboring country bent on invading us should get a say in whether or not we open the borders for them". OK, maybe they don't, but what if our borders are already open?

You can't invade our country!!!! ... because we welcome everyone.

eternal September?

@skillpatrol But that's the price you pay for an open site, right?

@MAFIA36790 "it is said so"?

always

@MAFIA36790 Correct. Were you also told off when you posted questions?

@barrycarter It's a mixture of a meritocracy and a democracy: You're trusted with a vote when you get 15 rep, before that, you're indeed not part of the voting process. And people will probably not give much weight to your opinion if you're a <100 rep user that's only been a member for a few days. And, finally, the moderators still reserve powers of unilateral decision making; although they were elected, there are no "checks and balances", this is not a constitutional democracy :P

It's like you're saying "we're happy with the democracy we have now, so no more voting"

@barrycarter : see this page. Physics stack exchange is is a question and answer site for active researchers, academics and students of physics and astronomy. It isn't for schoolkids who want John Rennie to do their homework for them. But having said that I think too many good questions get closed or improperly marked as a duplicate, And that too many good answers get downvoted, by people who don't contribute much to the site.

@ACuriousMind There's no constitution here :P But I believe you are actively driving people away from becoming better higher-rep users. You're method of question closing isn't giving people a fair chance.

@JohnDuffield The key word there being "students". At what point did we decide people studying physics aren't students of physics?

@barrycarter A "fair chance" at what? If you mean I'm not giving them a chance to make this site into something it is not and what I think it should not become, then that is completely correct.

@ACuriousMind Keying on the phrase "what I think it should not become", you're saying that your opinion is more important than that of new users, even ones who gain merit?

@MAFIA36790 As @ACuriousMind gave the analogy, plenty of people we are turning away from the site would change it to something you don't want, but the majority/meritocracy wants.

@MAFIA36790 I think even the closing templates are rude and suggest we don't want these people coming back.

what does it mean when someone says addition and multiplication on $\mathbb{Z}/n\mathbb{Z}$ are reduced mod $n$? I thought reduce meant to find either an equivalence class mod $n$ of some integer $a$ or to find the smallest nonnegative integer that is congruent to some integer $a$ (the least residue of $a$ mod $n$).

@Obliv It means a (mod n) * b (mod n) = a * b (mod n)

@MAFIA36790 But whose standard. You're saying the standard was defined by the users, but now it's fixed?

why wouldn't it just say distributive..

@Obliv That's not the distributive property.

@Obliv "mod n" is not something you multiply. It's an operator.

isn't multiplication an operation..

and I thought of it as $a$ mod $n$ where mod is the operator

not $mod~ n$

@barrycarter Not really. It is not "my" opinion alone, it is policy that came out of long and arduous meta discussion. Also, for the question of whether I vote to close a certain question, of course my own opinion is more important than that of others - these things are called "votes" for a reason.

@Obliv Well, yes, multiplication is also an operation. OK, 7 times 8 in mod 3. Because 7 is 1 mod 3 and 8 is 2 mod 3, the answer will be 1 times 2 or 2 mod 3. Now try 7 times 8 and take it mod 3.

@MAFIA36790 @ACuriousMind I see it as: you guys are happy with the way the site is now, and are working hard to make sure no one, not even people who have merit, can change the site.

I called it an oligarchy earlier, and I still believe that.

it's still 2

@Obliv Yes, that's the point :)

@barrycarter The point is that I am not more powerful than the other "people who have merit". If a majority of the active >3k users disagreed with the current state of closing questions, then why are they not reopening the questions?

@Obliv You can mod first and multiply or multiply and then mod, same answer.

kk

@ACuriousMind I'm saying you aren't letting new people get to 3k.

You have this fixed group of people who behave the way you want, and you won't let other people change it, even though they have the "right" to do so.

The group is not fixed!

@Obliv You are correct, mod is the operator.

it actually is kinda like distribution. Instead of $ac + bc = (a+b)c $ you have $(a (mod~ n) + b (mod~ n)) = (a + b) (mod~ n)$ don't you see the similarity?

@ACuriousMind But I say you're trying to make it so.

@Obliv Well, we're talking about multiplication here, though.

yeah but they're both 'reduced mod n'

@Obliv Not really. The fact that we write functions in infix notation doesn't mean .... oh wow, now I suddenly do see it.

@Obliv OK, we can say they're congruent mod n then

@barrycarter Well, you're wrong. I have nothing against new users that contribute what I consider high-quality content. If I tried to make the group fixed, I wouldn't give out any upvotes. If I thought we don't need new users, I would downvote every question from them on sight without ever reading it.

@ACuriousMind "what I consider high-quality content". That's the point. You kick out non-like-minded users... or at least send them on their way.

@MAFIA36790 How many people in reality?

There are good people here who intentionally ignore the guidelines.

@MAFIA36790 Like @JohnRennie gives out hints on homework problems, which violates both the "this is not a forum" guideline AND the "no homework help" guideline.

There are plenty of closed questions where good people have given answers (sometimes even accepted ones) or helpful comments.

@MAFIA36790 No, but he does to some. He clearly doesn't 100% support the policy.

@MAFIA36790 He openly admitted that he was deviating from the guidelines.

@MAFIA36790 The policy is no homework help unless two conditions are met, one of which is almost never met.

@barrycarter I just close content that doesn't fit the currently agreed-upon guidelines. If I let content slide that doesn't obey the guidelines, what is the point of having policies in the first place?

You're terribly reminding me of this quote:

@ACuriousMind It's not closing questions I object to. I object to the harsh treatment of new users that makes sure they never return.

@barrycarter What "harsh treatment"?

Are you perhaps confusing me with CuriousOne? :P

@ACuriousMind Yeah, but it's a Community Sandbox. You don't own Physics

@ACuriousMind Not even giving them a link to other places they can get help.

@ACuriousMind I vaguely remember talking to him too, but I don't think so.

@JohnDuffield There is a difference between "do my homework" and "help me with my homework"

@barrycarter I don't consider simple inaction to be "harsh".

@ACuriousMind Unfriendly. Unwelcoming. Rude.

It's the whole "I was here first" entitlement mentality that the Puritans had and the Native Americans unfortunately didn't.

@ACuriousMind I'm pretty sure he understands ;)

when you say $a = 2~mod~4$ and $a^2$ do you do $2^2 ~mod ~ 4$ or $2^2~mod~4^2$?

that makes no sense 1 sec

@Obliv Hint: 10^2 is just 10 * 10

I think it's a lousy analogy.

@barrycarter Well, I simply don't agree that it is that. If someone asks me a question I don't want to answer, a simple "No." is not rude.

It ain't your frickin' sandbox!

@ACuriousMind But they're not asking YOU, they're asking the community :)

@barrycarter Yes, and the five votes required to close a question together with the possibility of three leave open votes stopping the closing process is intended to make closing reflect a community decision.

We can't have a frigging SE wide vote asking every user for every question whether it is on-topic or not!

I don't know what you want

@ACuriousMind 5 isn't a great many, ... what do you mean SE wide vote?

Ooooh.

Tell us exactly what you @barrycarter want.

@MAFIA36790 Mostly the same 5.

@skillpatrol I want this site to more represent the people who visit it and ask questions, even if these people are newbies.

@barrycarter And yet, the close queue moves achingly slow even in the cases where there is consensus. Any more votes needed and I can tell you we could not keep up with the volume of questions coming in.

But @ACuriousMind you just gave me an idea. I forgot that anyone on SE can join Physics and re-open questions.

@barrycarter No, they can't

Too vague. @barrycarter

@ACuriousMind Vote for re-opening?

You need 3000 reputation for close and reopen votes.

@skillpatrol Have you read the actual site policies? They're vague.

yup

@ACuriousMind 3000 sitewide or on the actual site in question?

@barrycarter : I agree that there's a difference between "do my homework" and "help me with my homework". But you should agree that the issue goes deeper than that. When somebody says I have nothing against new users that contribute high-quality content, sometimes it isn't always true. Some people who like to tell you they're the "expert" don't like being corrected.

@barrycarter It's a per-site privilege

@MAFIA36790 I just think you could do a better job of keeping people on this site.

@ACuriousMind Oh, so I can't do it here... and I can't have people from other sites "invade" Physics either.

@MAFIA36790 But I can expect the people who actually DO clear the queue to behave a little better.

@barrycarter : what you don't know is that I started getting mass downvotes when my rep got to about 2.5k. Within seconds of answering a question. Before anybody could have even read the answer. Unfortunately for some I happened to answer a hot network question and broke through the 3k barrier.

OK, ultimately, I'll say that Physics is a tremendous anomaly from the much friendlier other Stack sites. That's bad for consistency, and I feel that the high-rep users here are intentionally preventing people from using the site to change the policies.

@ACuriousMind I'm not sure how that's relevant... who was downvoting you and why?

@barrycarter what?

@MAFIA36790 No, that's not your fault :)

I didn't say anything about people downvoting me

@ACuriousMind You said something about getting downvoted rapidly.... "what you don't know is that I started getting mass downvotes when my rep got to about 2.5k. Within seconds of answering a question. Before anybody could have even read the answer"

@ACuriousMind it was an answer to JD, which you couldnt read...

@barrycarter No, I didn't say that, unless I'm going insane

crap, sorry

Disregard.

Oh well, I don't expect that arguing my position will help, but it was cathartic.

@JohnDuffield I actually used that exact word earlier :)

$2^{10} (mod~100) = 24 (mod~100)$ , $2^{10^2}~(mod 100) = 24^2(mod~100) = 76 ~mod~100$ Is this correct? I see what you mean by it being different @barrycarter since it seems you leave the modulus in every time to show that it's a modulus on $100$.

@barrycarter : good man. It's a bit like the EC. It pretends to be democratic.

@Obliv That didn't come out quite right

i always need preview apparently :p

@Obliv Yes, what you did is correct.

There's a preview here?

no but I meant the one for posting questions/answers on the main site

@MAFIA36790 That was to @Obliv They implied there was a way to preview TeX before posting it.

I can always check my tex there

I use texpaste.com

But not in chat, only in posts.

Only when I'm drafting posts locally before I start typing them into SE

you actually use tex? :') @barrycarter

@Obliv In my posts yes :)

There are only two real ways to fight this battle: convince SE in general that Physics is enough of an anomaly that it requires special treatment... or lead a revolt to oust the oligarchs.

$\LaTeX$

@MAFIA36790 You will never stop us! We number in the mil... thou... ok, I think I got one other guy maybe.

$LaTeX in TeXas$

I wish physics was able to explain the brain. One of the other things that I want to study but I can't because I'm majoring in physics :c

like how do neurons generate memories it's crazy

@Obliv Ah, the Fowler-Cooper debate.

actually idk what does

@Obliv It's presumably engrams.

I don't even know WHAT those are. I knew once, but I've... uh.. forgotten.

@MAFIA36790 : it's just how it is. The stack exchange model is somewhat idealistic, it doesn't really handle collusion/gaming/dishonesty, and the business model seeks to paint a rosy picture. As for what I said, look at my answers. Try to watch what happens to a new one.

I feel like it can't be as simple as the shape of the brain. maybe it's the structure within the parts of the brain :O like micro-structures if that makes sense @barrycarter

@JohnDuffield I love you like a brother especially since you sent me an autographed copy of your book... but I think your issue is a little bit different from the one I'm talking about. Your views are wonderfully interesting, but don't appear to be mainstream.

@Obliv engrams are presumably loops of cells

@Obliv My physcis teacher back in school has actually been a reasearcher for brain acitivty scans via MRT. So there's still a way to bring your interests in one direction :)

*(massive type correction)

**typo

@barrycarter : I'm the one who quotes Einstein/Minkowski/Maxwell/etc.

@ntor interesting :p I will definitely keep my eyes open to all available paths

@JohnDuffield I think we talked about this. The first person to discover something isn't always 100% correct.

@MAFIA36790 : because I get instant downvotes before anybody can have even read the answer.

@MAFIA36790 : what heated arguments? Apology accepted anyway. If we all agreed about everything life would be so dull.

Anyway, I have to go. Bye all.

@JohnDuffield Well, flatly contradicting Einstein isn't always wrong. But they do claim to have the experimental support. BTW, you believe that smell is due to the motion of molecules? Bye.

is $(\mathbb{Z}/n\mathbb{Z})^{\times}$ the set of congruence classes that have multiplicative-inverses?

cya later

Motion is king, barry. Bye. Oh, and if they have the evidence, that's fine. The evidence trumps Einstein. And everything else.

\o

@Obliv It's the group of mod classes under multiplication. It's not a group.

What? $R^\times$ generally denotes the group of units ofthe ring $R$

So, yes, @Obliv, $(\mathbb{Z}/n\mathbb{Z})^\times$ are all elements in $\mathbb{Z}/n\mathbb{Z}$ that have a multiplicative inverse

@ACuriousMind Ah, OK. I was going to point it's not a field for most values of $n$, but it is sometimes (leaving @Obliv to figure out hen)

I don't know what a group or ring is yet I will soon enough I guess.

by elements in $\mathbb{Z}/n\mathbb{Z}$ do you mean congruence classes mod n @ACuriousMind

Yes

groups, rings, fields = the 3 basics of abstract algebra

@ACu Does this click you?

yes

@A but this does NOT click everyone whose name starts with A?

No, that does nothing

I think it pings as soon as the name is uniquely identified

Shortest non-ambiguous abbreviation?

@bar I love me

No click, but I don't think you can ping yourself anyway.

@bar

does it work

@O That worked, thanks.

nope

@Ob now?

nada

obliv is short enough I think :p

@Obl and now?

There may be a 3-letter minimum

true

You're the only completion for "O" here

@Obl did this work?

yes

@0c

Sniff, sniff.

might work for 0celo7

I miss the Ocelot.

I know @0 didn't work.

what if I made an account called barycarter? then @bar should ping for both of us?

or it has to be unique with a minimum of 3 characters maybe

@Obliv No, it's the shortest non-ambiguous. You'd have to specify enough letters to make it one person

Yes, that's what I'm thinking: two rule combo.

Go for @barycenter ... it's a pretty cool name

is that what your parents named you after?

lol

@Obliv I was always the center of their universe :P

Until that stupid little girl came along.

marrycarter? @bar

gottem

@Obliv I'm flattered, but we've just met...

i thought you meant your sister lol

@Obliv Oh, yes. I call her "Carrie Barter" though that's not actually her name.

@Obliv My joke was left half-finished, but I felt it was dumb, so I left it.

lol

How can elements in $\mathbb{Z}/n\mathbb{Z}$ have multiplicative inverses in $\mathbb{Z}/n\mathbb{Z}$? Like if $n = 4$ then how can $\bar{3}$ have multiplicative inverses such that $\overline{3c} = \bar1$?

What's 3 * 3 ?

9

And what's that mod 4?

I forgot to mod..

didn't realize it was $\bar 1$ instead of $1$

(some comment about moderation here)

@Obliv The definition of a multiplicative inverse that a times a^-1 = identity

Actually, that's also the definition of a group inverse.

By 1 with bar over it, you mean 1 inverse?

no that's just the congruence class of 1 mod n

Oh, OK

the multiplicative inverse doesn't seem intuitive. 2 * 2 is 0

that doesn't reach the identity $\bar 1$

@Obliv A number $m$ has a multiplicative inverse mod $n$ iff m and n are relatively prime.

2 does not have an inverse mod 4.

oh I see.

Not a multiplicative one anyway. Does have an additive inverse.

the multiplicative inverse isn't always the number $m^2$ right?

for $n = 5$ 3 is relatively prime to 5 and $3^2$ is $\bar4$

@Obliv Correct. Not all numbers are their own inverse.

ok

What is the difference between a (hypothetical) dipole antenna operating in the visible range and an 'ordinary' source of light, such as an LED? Why is there ongoing research on such antennas, and could a light source be considered an antenna in this sense?

@ACuriousMind Do you have a reference suggestion for instantons? My class is covering them really fast.

@knzhou None I can recommend, from my viewpoint, the stuff is scattered all over the place

There are many things that say they're "introductions" to instantons, but they almost all tend to bombard you with things you have to take on faith when it comes to stuff like the Chern classes