08:00 - 18:0018:00 - 22:00

6:01 PM
and yet everything is still terrible!

@ACuriousMind I suppose that is true :P

@AaronStevens As for the specific question, I'm not sure it's "engineering" so much as "non-mainstream" - trying to capture "virus spectra" doesn't seem to be a regular task for any kind of experimental physicist. We don't help theorists workshop their half-baked theoretical ideas, so we shouldn't help experimentalists/engineers/whatever workshop their half-baked experimental/engineering/whatever ideas either

Clearly $\mathbb{R}^{-1}$ is the $-1$'th dimension :p

@ACuriousMind Yeah, that is a good point for that question.

6:02 PM
Sometimes the empty set is defined as dimension $-1$
It is practical in some circumstances

2 hours ago, by ACuriousMind
This isn't "philosophy", you're just saying things that don't make any sense physically

@ACuriousMind I usually just try to see if the OP is asking about understanding any physics concepts. To me they aren't asking about understanding the techniques and concepts they wish to apply here
They just want to know how/if to use them

If you define the dimensions of simplexes, then the empty set is indeed the dimension before points
and this does pop up in formulas for the number of simplexes in $n$-simplexes or measure polytopes

what's next, fractional dimensions?

@AaronStevens Well, but that's exactly the tricky thing about experimental technique questions - they never are about understanding a concept, they are about building a working thing out of real materials with things you realistically have available in the lab.
There might be concepts involved in the design but it's really hard to tell from the question whether the answer will involve some insightful physical explanation of how to MacGuyver a thing together or whether it will be "Yo, ACME PhysicsStuff has exactly what you want on sale for 30 bucks"

6:09 PM
irrational dimensions, imaginary dimensions??

Hm, what was the formula again
I think for $n$-simplexes, it was like

that's of course the extreme ends of the spectrum, you'll also find anything in between, but regardless - you can't tell from the question which type of answer it'll get

$(2 + q)^n$ or something
Such that $q^d$ is a $d$-simplex

@ACuriousMind Shouldn't an experimental techniques question still be about understanding the physics concepts about and/or behind those experimental techniques though? they are about building a working thing out of real materials with things you realistically have available in the lab. seems to fall into that engineering close banner situation

$n = 0$ is $1$, so a point
$n = 1$ is $2 + q$, so two points and a line
$n = 2$ is $4 + 2q + q²$, and I guess this isn't the formula
what was it

6:12 PM
Our "consensus" seems to essentially be that the line is blurry and we'll hash it out on a case-by-case basis

Ah, there we go

Which works until people try to cite the text of the close reason at each other as proof of a completely different consensus because they weren't here to witness the discussions years ago ;)

It's $(a + 1)^{n + 1}$, such that $a^n$ is an $(n - 1)$-simplex
and therefore, constants are $(-1)$-simplexes, which are just the empty set and do not count

@ACuriousMind I guess that is fair. So basically don't take the engineering close banner too seriously?

So not counting constants, $n = 0$ is $a$, a point, $n = 1$ is $a^2 + 2a$, $n = 2$ is $a^3 + 3 a^2 + 3 a$
and things all match up

6:16 PM
@AaronStevens Well, if you have a better text to propose, by all means do so! Took us only half a decade to improve the HW-close text right before they hid it from almost everyone's eyes anyway, so what could go wrong?

Since simplexes can be done just using set theory I think those may just be combinatorial formulas
$(2 + a)^n$ was actually correct, but for measure polytopes
ie cubes and whatnot

@ACuriousMind Haha yeah exactly. I think I would need to read through more meta posts, and look at examples of closed engineering questions and border-line open questions to even begin to propose a change. I certainly don't have the time for that at the moment
I probably just need to get a better feel for how questions like those should be approached first

user434058
Yesss!!! I used all my flagggsssss!!!!

user434058
Seems like "study from home" has attracted a lot of HW questions...

@AaronStevens we appreciate you bringing in these questions :-)

6:20 PM
In mathematics, an abstract polytope is an algebraic partially ordered set or poset which captures the combinatorial properties of a traditional polytope, but not any purely geometric properties such as angles, edge lengths, etc. An ordinary geometric polytope is said to be a realization in some real N-dimensional space, typically Euclidean, of the corresponding abstract polytope. The abstract definition allows some more general combinatorial structures than traditional definitions of a polytope, thus allowing many new objects that have no counterpart in traditional theory. The term polytope is...
that's the stuff

If the virus spectrum question asked if there is a useful optical spectrum that can be obtained from virus protein, then I guess it'd be on topic here. AFAIK, most protein spectra are actually using mass spectrometry. However, UV spectroscopy of proteins is a thing; see microspectra.com/support/learn/protein-absorption But I don't know how useful it is for detecting specific viruses on a surface.

@Slereah for the win!

@skullpatrol It's not 2007 anymore!

Yeah, I usually tend to be more strict about closing questions, which I feel bad about sometimes.

@skullpatrol Greetings! I've not been here for a while. Polytopes? I've met the Tope family once, Poly was the nicest...

6:23 PM
@TerryBollinger Welcome!

@AaronStevens Don't feel bad - it takes five to close a question, after all

user434058

So when you're wildly off-base the worst that happens is that some people will have to click "Leave Open" :P

@ACuriousMind That and certain users label me as an oppressor :P

Oh, they'll do that anyway.

6:26 PM
::mumble mumble:: :P

user434058
I feel I am strict in flagging, but you can allow flagging inaccuracies because anyways someone else is gonna take the final decision!

Yeah, that doesn't actually bother me too much haha.

I recently tried to advise a homework dumper that their language was (possibly accidentally) off-putting, but they didn't appreciate my advice...
I suspect that English is not your mother tongue, so you may not realise it, but telling people to "Sketch the setup" and "Give complete answer" is rather rude. If you would like volunteers to help you please do not order them around like slaves! — PM 2Ring Mar 27 at 9:19

They didn't appreciate it or want to follow it :)
There are users like that from time to time. They think if you know the answer then you have no other choice but to post it

Hm
I wonder if the empty set also has topological dimension -1
"The covering dimension of a topological space X is defined to be the minimum value of n, such that every open cover C of X (regardless of ply) has an open refinement with ply n + 1 or below."
Yeah I think so
Zero sets will cover the empty set
Hence $n = -1$
$$\varnothing = \bigcup_{A \in \varnothing} A$$

6:33 PM
What's ply

toilet paper

@AaronStevens I like the ones where they try to goad people into posting answers by saying things like "Clearly this is being closed because no one here knows how to answer it."

"The ply or order of a cover is the smallest number n (if it exists) such that each point of the space belongs to, at most, n sets in the cover."

user434058
@Slereah Did you run out of plies?

I've got plenty

6:35 PM
@JMac Yeah. Really we just like to keep our lofty physics knowledge to ourselves

user434058
And I really like to flag 'em!!

I would say $n = - 1$ doesn't make sense by that definition of ply

Since ω is the first limit ordinal, I reckon zero should be considered to be the zeroth limit ordinal. Consider, it's not the successor of any smaller ordinal...

@bolbteppa Indeed it doesn't, but note that there's a "ply of n+1" in the definition of Lebesque covering dimension
Slereah is right that the empty set has -1 covering dimension because it's covered only by the empty cover, which obviously has a ply of 0

aha!
poor secret

6:37 PM
Well, every set is a cover of the empty set

@ACuriousMind Lebesgue

but it is the smallest cover!

@PM2Ring Eh, it's all French to me

In mathematics, the Lebesgue covering dimension or topological dimension of a topological space is one of several different ways of defining the dimension of the space in a topologically invariant way. == Definition == The first formal definition of covering dimension was given by Eduard Čech, based on an earlier result of Henri Lebesgue.A modern definition is as follows. An open cover of a topological space X is a family of open sets whose union contains X. The ply or order of a cover is the smallest number n (if it exists) such that each point of the space belongs to, at most, n sets in the cover...

In physics and mathematics, the dimension of a mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any point within it. Thus a line has a dimension of one (1D) because only one coordinate is needed to specify a point on it – for example, the point at 5 on a number line. A surface such as a plane or the surface of a cylinder or sphere has a dimension of two (2D) because two coordinates are needed to specify a point on it – for example, both a latitude and longitude are required to locate a point on the surface of a sphere. The inside of a cube...
I thought this was the Krull dimension

6:40 PM
lol

In topology, a discipline within mathematics, a negative-dimensional space is an extension of the usual notion of space, allowing for negative dimensions. The concept of negative-dimensional spaces is applied, for example, to analyze linguistic statistics. == Definition == Suppose that Mt0 is a compact space of Hausdorff dimension t0, which is an element of a scale of compact spaces embedded in each other and parametrized by t (0 < t < ∞). Such scales are considered equivalent with respect to Mt0 if the compact spaces constituting them coincide for t ≥ t0. It is said that the compact space Mt0...
2

I was wondering, why are bad people put in jails?

What kind of a definition is this

That question is dripping with assumptions :P

user434058
@NovaliumCompany So they don't come back to do bad things.

6:42 PM
they broke the law

They are not
They are put in the WHITE HOUSE

user434058
@Slereah But that's just for one bad person. The rest are hopefully in the jail.....

@NovaliumCompany well you don't want a serial killer to wander freely!

@NovaliumCompany So they can teach young criminals how to behave like proper criminals.

Why do they lock them up? Why can't they just put them to sleep for 5 years and then wake them up afterward? In that way, no one has to worry about them. Smaller jails and cops can do other jobs than baby sitting.

6:44 PM
haha
I thought this was going to go another direction, but no

Why can't I be put to sleep for 5 years
I could use a nap

@bolbteppa I've read it five times and I still have no idea what it's trying to say

user434058
@NovaliumCompany How do you make someone sleep for 5 years? Like, either kill him or let him live, you can't just choose a path in between......

@NovaliumCompany ??? In what dream world do you live where we can just put people under for 5 years?

Coma.

user434058
6:45 PM
@NovaliumCompany Coma at will, is a superpower........

Also, why'd you put them to sleep for 5 years? What exactly are you trying to achieve?

@NovaliumCompany You could come up with so many reasons, especially if you're really cynical. I think the ideal use of jails in a modern "Western" society is for rehabilitation and for safety of others where applicable (maybe I'm using Western wrong). For a more cynical example though, many people think that the US prison system is being manipulated for profit of those who own them, thus encouraging more prisoners.

I would advise not to go along with @NovaliumCompany's long rambling sociology-related questions
They never go anywhere and he will never learn

@PM2Ring well that kind of language is usually used on Quora and other q and a forums and hence they think it would be acceptable over here too.

@NovaliumCompany did you see my link?

6:46 PM
@Slereah The problem with that is that it'd take you about 10 years to catch up on the stuff you missed during your 5 years of sleep. ;)

@JMac They put them in jails so they can learn from their mistakes, never repeat them again, and teach youngsters not to repeat their mistakes. Got it.

@PM2Ring I don't even read the news now

@skullpatrol no

???

user434058
@JohanLiebert Quora is a garage sale where you find all weird things of exploited quality....

6:47 PM
7 hours ago, by skullpatrol
@NovaliumCompany do any of these tables make sense to you?

@skullpatrol Oh yes, I saw that
@Slereah That's a pretty dumb assumption.

@Slereah Given the last decade, do you really want to see what the world looks like in 5 years without the mercy of gradually slipping into it so you don't notice it so much? :P

@FakeMod well it is a kind of q and a social media. And they have (kind of) their own John Rennie known as Sean Kernan.

@NovaliumCompany Well let's see how everything unfolds

@Slereah Me neither. It's not good for my mental health. So I get most of my news 2nd or 3rd hand, via the places I hang out online, like here. Although I do occasionally Google stuff when it comes to my attention that something significant is happening that may directly affect me.

6:49 PM
@ACuriousMind At least I won't have to go to work after the apocalypse

You will have to go to work...IN THE MINES!

@Slereah JMac pointed out the reasons. So I now understand why it's better to have jail than long sleep.

user434058
@JohanLiebert It's good as long as their JR (or equivalent) answers the question, but for the other people, they just troll....

Is it better to have jail than long sleep

@Slereah yes.

6:50 PM
Long sleep isn't an available option, but jail is also terrible
People tend to get worse in jail

Plenty of people prefer "no jail" over "jail"!

@FakeMod Kalpit is active there.

@Slereah why are there so many definite articles in the translation of this? "L’écriture est la peinture de la voix; plus elle est ressemblante, meilleure elle est."

user434058
@ACuriousMind If you like to wonder about apocalytic future then this video might interest you 👇 Moreover, it's a German channel.....

6:52 PM
@skullpatrol Because it's abstract notions
not specific objects

I see, thanks.

user434058
@JohanLiebert Kalpit Veerawal......Yeah few others too, but they mostly answer non technical questions...

What happens if for those 5 years in jail you play (day and night) an audio clip of someone repeating: "I will be good"? Here's something funky to think about.

user434058
@ACuriousMind I propose death penalty for heinous crimes.....

user434058
@NovaliumCompany You'll get bored!

6:53 PM
@FakeMod ....sorry, what?

African trypanosomiasis, also known as African sleeping sickness or simply sleeping sickness, is an insect-borne parasitic disease of humans and other animals. It is caused by protozoa of the species Trypanosoma brucei. Humans are infected by two types, Trypanosoma brucei gambiense (TbG) and Trypanosoma brucei rhodesiense (TbR). TbG causes over 98% of reported cases. Both are usually transmitted by the bite of an infected tsetse fly and are most common in rural areas.Initially, the first stage of the disease is characterized by fevers, headaches, itchiness, and joint pains, beginning one to three...

user434058
@ACuriousMind the vid below.....its interesting for people who think about an apocalyptic future....

@NovaliumCompany That might turn into some sort of mild torture. I don't think listening to a voice repeat "I will be good" for 5 years would actually make you good. I suspect if that happened to me, and I were let out after 5 years, if I ever heard the phrase "I will be good" afterwords, I would freak out.

@NovaliumCompany I've said this before but you really would benefit from reading classic philosophy and literature before throwing around ideas as if they're new :P
In this case, you're just doing the "You love Big Brother" bit from 1984.

Also you would benefit from not throwing random ideas
Might as well say "What if instead we fed them bananas"
About the same probability of that giving results!

6:58 PM
@FakeMod Sorry, I'm well aware of the nuclear destruction we could wreck upon the world. I find it somewhere between disheartening and terrifying, not "interesting"

Is the problem that I'm throwing those ideas around, or that I'm having them?

user434058
@ACuriousMind Interest is subjective.... No problem.

Because I believe I have the right to not be judged on my thinking.

I would guess there are many problems
Yet another wrong idea!

Actually, no. Judge me however you like. lol

6:59 PM
throwing without thinking pal

@NovaliumCompany The problem is that you seem to think you're being very original when this is well-trodden ground, while continuously telling everyone that you think education is a waste of time.

@skullpatrol Here, I'd agree.

:-)

user434058

Okay, I'm just going to leave. I guess I'm currently not beneficial for this chatroom. Have a good day all. <3

user434058
7:00 PM
Education is awesome if the educator is awesome!!

@FakeMod indeed!

@JohanLiebert Thanks, I'd rather take my chance with the cryogenic people

@NovaliumCompany I think most people would agree that judging based on thinking is bad (thoughtcrimes and such). Thankfully people aren't mind readers, so typically people judge based on the thoughts you share and how you share them.

In other news, I find the new "follow" feature extremely annoying. Not because of it's functionality, but because I click the "follow" button every single time I try to copy the link to a question!

Indeed @JMac "Writing is the painting of the voice; the closer the resemblance, the better it is."

7:06 PM
@ACuriousMind I find it annoying for a different reason. Practically every page I visit reminds me of the feature. I don't like having little bubbles on top of my page, especially when they are redundant.

I guess it won't take long to get used to it, but I've already clicked follow several times when I meant to click share. Muscle memory is a powerful thing... — PM 2Ring yesterday

@ACuriousMind that issue has been raised on mother meta and it is under .

user434058
@ACuriousMind I don't know much bout it, but can't you write a greasemonkey script to interchange the positions or hide the follow option? Just givin an idea.....

55

feature-request status-review Could you move this button to the right? We are used to the share button on the left, and the "edit" button on the second-left. It's not very user-friendly to change the order of those buttons, and wastes users' time whenever they try to perform the action th...

7:12 PM
@FakeMod I'm not touching the abomination that is JavaScript just to undo them moving my cheese!

user434058
@ACuriousMind That's a really metaphorical sentence, but I understand....

@NovaliumCompany which answer did you choose, pal?

I am guessing this one is probably a valid PSE question?

@AaronStevens Not so sure, looks more like a question about how exactly error propagation works to me
I mean, might be a valid question, but I don't see what it has to do with technique

7:23 PM
Man I lucked out pretty hard with HNQ's over the last week. Two of my answers in a row went HNQ and were the top answer on the questions.

congrats

@ACuriousMind Ugh. Oh well :)

1

"I'm a laywoman in physics and recently found myself pondering..." Given that you articulated your query so clearly despite this self-assessment , we should all wait for the questions you ask when you are no longer a laywoman in physics. $(0)$ I'll start off by saying that in my opinion, the f...

There are some meta text in the answer which i think should be removed.

@JohanLiebert Then remove it! Or flag it for moderator attention if you think a moderator should do it.

@skullpatrol China

7:29 PM
coolio

@ACuriousMind done.
Well I am not going to do that again. He/she has just put a rant there for me as well.
It may look like a rant to you, but it makes an important point regarding the culture here. We (at least I) come here to do physics. This is important. So let it be. Also, as a general rule, CENSORSHIP is not healthy for democracy. Just saying. — insomniac 3 mins ago

disengage pal

@skullpatrol yeah that's the reason i left the moderation stuff.

hmm

*one of the reasons

7:44 PM
Well don't worry, I'm willing to dive into that. His response seemed self-contradictory (I'm here for the physics, but also here's a rant about the culture on this site as opposed to anything about the physics). To me it seems like another issue of not understanding the site culture and taking it personally.

the system should create a chatroom soon
bingo

@skullpatrol Is "the system" ACM's new nickname? I like it.

:-)
you can't beat "the system"

"the system" works

"The system" is ruining democracy!

user434058
7:53 PM
I will hack "the system"!!!!!!!

I saw the system.

Not sure whether that's a lewd suggestion or a threat. Possibly both...

user434058
@ACuriousMind oops "the system" got overheated....;)

@FakeMod you're a fake system :P

user434058
7:54 PM
Just jking

user434058
@skullpatrol Yes, proudly, I am!

I think jk stands for just kidding

user434058
@Charlie I thought it meant joking.....

People say jk by itself
sometimes at least

@FakeMod It definitely stood for "just kidding" in the context I had been using it.

user434058
7:56 PM
@Charlie Point taken! Thanks!

wouldn't be much of an abbreviation to just leave out one letter, would it? :P

@FakeMod pseudo system?

user434058
@JMac No doubt! But I am not a well versed chatter.

but then again, I thought for years that 'smh' stood for 'So much hate', sooo....

user434058
@skullpatrol No fake is more sloppish

user434058
7:57 PM
@ACuriousMind No I def know tht means shakin ma head

user434058
Credit goes to memes....

@ACuriousMind so what does it stand for then?

@ACuriousMind Hahaha I always had assumed the same thing until one day I decided "that can't be right" and looked it up.

In Australia, SMH is an abbreviation for a major newspaper, the Sydney Morning Herald.

7:59 PM
A Curious System that Works

> The concept of negative-dimensional spaces is applied, for example, to analyze linguistic statistics.

user434058
@ACuriousMind Like isn't lewd used for some obscene sexual stuff??

what the

@FakeMod Yes. Please don't make me explain my stupid jokes :P

user434058
And I didn't mean anything sexual?

user434058
8:01 PM
@ACuriousMind Oh! No problem!

@FakeMod You don't do your hacking in lingerie?
2

jokes are only funny once they've been explained in excruciating detail several times

user434058
@JMac I am a straight guy. And thus I don't wear lingerie.

user434058
And neither do I hack!?

@FakeMod Hey now. What's wrong with a straight man wearing a lacy bra and panties?

user434058
8:02 PM
"the system" might have experienced a glitch!!!

user434058
@JMac They look ugly on guys!!

user434058
At least they look ugly to me

@JMac isn't that called cross-dressing!

user434058
Transvestite, to be precise

@FakeMod That entirely depends on what you wear.

user434058
8:03 PM
@JMac Yeah, so I don't wear that.

user434058
And probably never would!

@FakeMod That's not more precise, just more derogatory
cross-dresser is considered the more appropriate term there

yeah I think transvestite is a perjorative, at least now

user434058
@ACuriousMind Please don't make me explain my stupid jokes!

user434058
Sorry!!

user434058
8:05 PM
Didn't know that!

user434058
That's the problem when you try using new words just because you know them.....

@SirCumference linguistic statistics is just saying things that don't make any sense physically :P

@JMac In this time of working from home, I actually mostly wear a bathrobe when hacking :P

user434058
@ACuriousMind I would rather be half naked as long as I am alone in the house.

I think my flatmate would object to me running around completely naked :P

8:07 PM
@ACuriousMind Is it at least a seductive bathrobe, or has all the semblance of civility been left behind in these trying times?

user434058
G00D N!G|-|T

cya pal

Dunno, is bright blue terry cloth seductive to you?
...wait, maybe don't answer that :P

I mean, yeah. There's nothing more attractive than being highly absorbent.

Censored

8:10 PM
(Don't dig into that... whatever meaning you take from it... it's not what I mean)

Ugh, I'll go get the brain bleach

BTW censored was meant for the above meta post

Don't post meta questions here before the bot does. It makes it sad ;P

Sorry Mr. Bot! Would never do that again.
OK! Good night.

cya pal
Quantum linguistic statistics

8:22 PM
-2

This relates to https://physics.stackexchange.com/a/540575/ . I said what I had to say on my answer itself. It was edited out by a moderator and suggested to me that I post my query here. I have no queries as such, but I do have (what I feel) an important point to make. Since I spent a good dea...

Why study Linguistic Statistics?

Linguistic Statistics is really useful for understanding research articles or writing research articles within the field. Many studies include statistics and it is important that you are able to understand them so that you are able to critically evaluate the study for reliability and validity.

8:35 PM
5 hours ago, by ACuriousMind
There are no negative dimensions, please stop talking nonsense.
I believe an apology is in order here :P
5 hours ago, by skullpatrol
don't worry about it pal :-)

@skullpatrol Look, that in some contexts there might be a well-defined notion of negative dimensions does not make anything Secret said there anything more well-defined. If you want to make a coherent argument that I'm wrong about that you're welcome to, but just finding random instances of other people using the phrase "negative dimensions" is no such argument.

I can't fight the system :-)

8:50 PM

you win

Remember what I said about "stoking the flames"? If you can't offer anything of substance, what are you exactly doing here except trying to prolong an argument that everyone but you dropped hours ago?

Sorry to interject, does anyone know of a reason that Xenon is a particularly good element to probe dark matter interactions with?
it's inert and has a lot of electrons which makes it somewhat easy to ionize I guess, but is there any obvious reason i'm missing?

I'm not sure what probing exactly you're talking about, but as a noble gas, I'd imagine you're at least safe from any chemical reactions mucking up your setup

ah I just mean in direct detection experiments
I guess so, i imagine non-explosiveness is a desirable property in extremely sensitive apparatus

8:59 PM
whose picture is that on your avatar? @Charlie

coolio

@Charlie Like this? science.purdue.edu/xenon1t/?tag=migdal-effect My guess is that liquid xenon makes a good target because it's cold, which makes it easier to measure any heat produced, it's chemically inert, so the electrons of an atom are localized to that atom, and it's got a high atomic mass, which maximizes the ratio of nucleus mass to electron mass.

That's actually the exact page I have up yeah, I hadn't thought about the temperature or the nuclear mass, that's a good point

There may be other factors I've overlooked, but I never heard of the Migdal effect before. ;)

08:00 - 18:0018:00 - 22:00