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9:00 PM
Apparently, roadworker and carpenter are STEM professions, but "mathematician" isn't listed anywhere.
 
mathematics is literally the M in stem haha
 
Lol @Semi, at least now I've started hearing more of the reaction to that
 
I was about to say
 
People are starting to catch on to how academia has gotten tight and tend to really encourage that you hedge your bets
 
9:01 PM
The other impulse I dislike is the suggestion of being an actuary
 
I know a lot of people who've been like "pursue a phd in stem, that way you delay joining the work force as much as possible" rather than for the academic career route
 
Though I suspect that's a prejudice on my part
 
I know a lot of people about to do maths degrees aiming to become an actuary
 
@Semi it apparently has pretty high career satisfaction
 
9:02 PM
I tend to associate actuaries with accounting and I'm sure that's too narrow
 
Oh the actuary suggestion is something I've heard quite a lot
 
it doesn't really seem suitable IMO
you would end up using, what, like 1% of your course material?
of course it's a good profession, but why is it targeted to mathematicians?
 
Wait do you mean like, they start by saying they want to be actuaries and then decide that math is the way to go to do it? Or do they start majoring in math and then go the actuary route?
 
yeah but most people don't use that much of the course material @Daniel, it's not a bad suggestion because math degrees teach you problem solving skills that are useful if you decide to be an actuary
 
I think it's the same reasoning as why you have physics PhDs going into finance.
 
9:04 PM
No, they start with an interest in maths and see how much money actuaries make
 
That's something I can kinda understand
 
@Semi finance usually uses way more math than an actuary does to my knowledge at least
 
@EricSilva Yeah I understand, but so does pretty much every STEM degree, I just don't see why it would be the best option
 
It's easier to retrain a physicist to know the relevant Econ concepts than to teach someone in business all of the relevant math
 
it's probably equally good to other stuff
 
9:06 PM
@EricSilva I can believe that
 
sometimes they actually use like stochastic calc and stuff
 
My main problem with finance is that, uh, it seems kinda amoral
 
@Daniel, it seems that navigating careers with a math major is tricky because a lot of neighboring careers rely on having field knowledge
 
@Semi I agree like pretty hard
@Daminark field knowledge isn't hard if you know how to learn new material is kind of the point
 
Like, you have academia but that's just way too tight
 
9:08 PM
math majors get exposed to lots of different things, so the prized skill isn't so much what you learn but your ability to learn mathy stuff
 
Right.
 
I guess computer science is a big one
 
And sometimes being good at math doesn't translate nicely to science, the only things closer to sure bets are compsci and stats
 
i have zero understanding (or confidence...) in discussions about the job market
i think i and most people in academia who talk about this have no idea about it
 
A physics background also tends to make you rather fearless about both math and programming
Which I'm sure is something that's appreciated
 
9:09 PM
Likely
 
getting a job is probably more about selling yourself than knowing anything anyway
or so im told
 
@MikeMiller Yeah. Ask an academic about the job market, and you'll get an academic's answer
 
all i know about is the academic job market and i only know about that to the degree one can
 
It's better to ask ex-academics that now have a "proper job" :P
 
@MikeMiller oh, a blast from the past: lately I've been getting interested in what I think you'd call instanton homology, albeit only the most simple version there of
 
9:12 PM
Most of what I know about the stuff is Lawler just sorta being like "Yeah so about that academia stuff... Don't get too excited about it... Make sure you have some compsci/stats, or science if you can do that"
 
So cycles generated as flows between critical points of a Morse function
 
Yeah, I would prefer to call that Morse homology
 
Right.
 
Instanton homology is a specific "instantiation" (hoho!) of this
 
9:14 PM
@MikeMiller that's actually relevant to me as I'm going to university this year - would you recommend going into academia within computer science?
 
Instanton in the sense of Yang-Mills?
 
Yeah
to @Semi
 
I know lots just go for a bachelors and straight into work, but I kind of want to explore the subject deeper
 
@DanielCastle Ask five different faculty members in computer science
Three of them young
 
Will do
 
9:15 PM
the numbers don't matter but younger people had a tougher fight
 
I'm literally only interested in the zero-dimensional version of this story, where the integrals are just plain old contour integrals
"Don't trust anyone over 30" is an exaggeration but it's in the right direction
 
Actually there's an REU associated talk starting basically now (read: when I arrive to campus) about how to jobs. Might do it
 
Don't trust anyone whose Bachelors degree was more than thirty years ago, maybe
 
don't trust anyone
 
9:20 PM
That's... Welp
 
Only trust people talking about their job if they're not interested in you becoming their colleague :P
 
haha good point
 
What are the criteria of interest aside from potential to succeed tho?
At least perceived potential
 
"Don't trust anyone whose CV is older than you are "
 
Okay that's beautiful
 
9:24 PM
lol
 
Demonark: Eric's suggestion about the Goursat proof of Cauchy's theorem is on the money. There one proves that holomorphic implies $\int_{\partial\Delta} f(z)\,dz = 0$ for any triangle $\Delta$.
 
perceived potential to succeed is not in any sense an objective measure
 
No $C^1$ hypothesis.
My generation used to say "Don't trust anyone over 30." And then we all turned 50 ... then 60 ...
 
no worries, we took your advice
 
Yes, that's what I started with above :P
 
9:27 PM
tbh right about now im wishing i wasnt doing gmt this summer
 
I didn't hear that.
 
What is it @Eric?
 
@EricSilva keep working at it
 
there are just so many theorems that are sooooo technical, like awesome results but sometimes it's pretty not fun
 
But, Eric, look at it this way. It's your protection from my asking about geometry questions you don't have time to think about. ... But yeah, super technical. I totally warned you.
 
9:30 PM
the thing is that you build a picture over time
 
@Ted to be fair, i didnt choose it, it was thrust upon me
 
and its a really beautiful process watching a picture form
 
You chose your mentor/adviser :P
 
of course i dont know shit about gmt
its 8 hours ahead of me but thats all i know
 
The default state of any PhD past a certain point is "I should be writing "
 
9:30 PM
@Mike, that is true, ultimately i do like it overall, and im gonna keep going
 
rolls 1 1/2 eyes
 
@Ted that's a fair point
although Schlag had apparently initially asked neves to participate because of me, so if i didnt go to his group, that might've looked really weird
 
Winning 8 Wimbledons is no picnic I guess.
 
rolls 5 1/2 eyes at PVAL
 
@MikeMiller but yeah, Morse homology
 
9:32 PM
In the end, it's all good, Eric.
 
at the end of the day im pretty glad im doing it, sometimes i wish i could spend all my time cooking though
 
well, that's not going to make you a living :P
 
@PVAL-inactive Not to mention publishing canonical textbooks
 
Stuff like "flow lines generated by d(Re f)/dz"
 
ideally eric would just be spending all day working on whatever riemannian geometry question i had on the mind
 
9:33 PM
lolol
 
He has a backlog of 3 or 4 I gave him.
 
(I'm almost certainly quoting that wrong)
 
Not to mention understanding Robert Bryant.
 
yeah but i care more about my questions
 
Trump is rubbing off on everyone. Damn.
 
9:34 PM
rip
im gonna go back to working now so i dont feel the guilt from not thinking about all the things i should
bye chat
 
Bye :)
 
There's a paper of Witten on this business I'll eventually need to sit down with proper
 
9:49 PM
Hrmf... is there any convention on where to split a long exact sequence if it doesn't fit on a single line?
 
Maybe where it goes down dimension (if it's like the stuff you get from homology with the connecting maps and whatnot)
Down or up
 
Well, I mostly mean, before or after an arrow :P
or have the arrow around which it's split on both lines or something
 
Draw a snake arrow, of course, from one line to the next.
Hi, DogAteMy.
That's where snakes came from :P
 
Draw little eyes on it as well
Can I repost a problem from earlier that Daminark and I were thinking about
 
Oh this reminds me of this one thing about long exact sequences which was funny
 
9:56 PM
So let $A$ be a downwards-closed family of subsets of $\{1,2,\dots,n\}$. Is there always an involution $f:A\to A$ such that $f(V)\cap V=\emptyset$ for all $V$?
Note that if $A$ has an odd number of elements, we can map the empty set to itself (as the empty set is disjoint from itself).
If $A=\mathcal P(\{1,2,\dots,n\})$, then taking the complement works.
 
What does downwards-closed mean?
 
If $U\in A$ and $V\subseteq U$ then $V\in A$
It's closed under taking subsets
 
@TedShifrin Ooh, brilliant, thanks
 
Oh.
(But I don't know how to typeset a snake in LaTeX, Steamy. :))
 
I'm sure it's been done before (re: LaTeX snakes)
 
9:59 PM
This was the photo
 
@Daminark lol
 
Very cool, Steamy. Where'd you find it?
 
Aww, I missed a prime somewhere.
I use the tikz-cd package for commutative diagrams
 
they have a snake command in there? :)
 
10:00 PM
The "snake arrow" is \arrow[out=0, in=180, looseness=2,overlay]{dll}{\delta}
 
oh so cool.
 
54
Q: How do you draw the "snake" arrow for the connecting homomorphism in the snake lemma?

Jamie WeigandtHow does one draw the "snake" arrow for the connecting homomorphism when using the snake lemma? I'd also be interested in drawing similar arrows act as "carriage returns" when considering a long exact sequence of cohomology. I'm sorry if this is a little vague. I'm hoping that someone who's alr...

 
@Danu would be proud of you. He loves tikz.
 
@Astyx have faith in LES
 
LES is more
2
 
10:01 PM
LES will never let you down
 
Salut, Astyx.
 
Salut
Comment ça va ?
 
Comme toujours :)
Y a-t-il des nouvelles?
 
Non, l'ENS n'a pas répondu :(
Ah si, je suis 17e au concours des Mines
 
17e? Et on accepte combien?
 
10:04 PM
20, donc je suis pris
 
Formidable, si tu t'y intéresses.
 
Mais c'est surtout que c'est sur 1866
 
20 sur 1866?
 
C'était mon troisième choix après Polytechnique probablement
Oui, mais il y a d'autres écoles qui utilisent le même classement
 
Mines, c'est où?
 
10:05 PM
Et beaucoup démissionnent pour l'X/les ENS/Centrale
C'est à Paris
 
Hmm, je ne le connais pas.
 
C'est une (très) bonne école d'ingénieur
 
Hey huys
Guys*
 
gi
 
Can one of you please have a look at my solution and tell me if I am correct or completely wrong?
https://math.stackexchange.com/questions/2361526/unknown-3x3-matrix
 
10:07 PM
@kthonenice Yes
Okay sorry I had to do that
 
Would you?
 
So wait you've executed those row operations on $A$ to get the identity, so now you want to find what the associated elementary matrices are, as well as what $A$ was, right?
Well you did that and are now trying to verify
 
You'd want to edit that line of matrices with the $^{-1}$
 
Yeah I will edit it soon guys
Yes I exectued the row operations and got the identity matrix for the unknow matrix A
Then worked my way back and found A (I hope)
 
Now I'll vanish
 
10:10 PM
But I am unsure if I am correct
 
Seeya later
 
See ya man
 
Bonne nuit, petit chou (that's totally what you frenchies say, no? :P )
 
"Frenchsters"
 
@Daminark did you see if my A was correct? I would appreciate it
 
10:16 PM
I'm not happy with it right now
The row switching of 1 and 3 seems like it messes it up
Like, to row reduce A to the identity, I'd just say -7r_1 + r_2 -> r_2
Then 3/2r_3 + r_1 -> r_1
Then 1/8r_3 -> r_3
 
That gets you the identity
 
@TedShifrin :) I think I have my own adaptation of the snake arrow. I don't like that sharp bend @SteamyRoot. LoopSpace's answer is more like it.
 
Well, his answer isn't for tikz-cd, and I prefer a smooth arrow.
Increasing the vertical separation would make the bend less sharp, though.
 
Im not looking for the identity matrix of A
I am looking for the matrix A
 
10:24 PM
No I mean like, the way to verify it would be to perform those row operations and see if it gets you the identity, that's how you would know that this is what you started with
But we don't
 
aaaah
Ofc. I didn't check that
 
So where do you mean I mess up?
 
@Danu Sharp bend is gone :^)
 
It's probably the row switching
If that step wasn't there, $A$ would've worked
So try again and be careful about that
 
10:33 PM
@SteamyRoot Want me to look up how I did it?
 
Already found it, but thanks :)
 
I don't like that large spacing, but that can easily be adjusted.
 
Well, yeah, I still had the vertical separation set to large
 
The TikZ code is kind of a mess though :(
 
I got it @Daminark
 
10:37 PM
Because of my $\dots$ and stuff it got a little complicated.
And I was very precise with where I wanted the arrows to start :P
 
Take a look at it now please. I think it is correct
 
10:53 PM
I'm looking to find an expression for the highest power of 2 in $3^a\cdot(2b-1)-1$ but the only thing I can find that's close is mathoverflow.net/questions/29828/… which doesn't really help me, any ideas?
Also, is it worth posting the same question in mathoverflow as math.SE?
 
11:36 PM
If anyone is interested, I have a graph theory proof that I'd like help with: math.stackexchange.com/questions/2372964/…
 
11:53 PM
okay, so $\pi^0$ = $1+0i$. 'Nuff said.
Any complaints, hit me up at my mailing address.
I've settled the definition for Platonic solids, too, to generalize to any dimension. Pay me later.
(sorry i can't help it. I'm without a university and bored in middle america.)
 

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