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18:01
@BalarkaSen do you think that the "obvious" map taking an elliptical disk into a circular one will be analytic?
i.e. just rescaling the two axes?
Also, I take it that it's "dear Prof ..." as opposed to "dear Dr ..." for an associate professor?
I say Dr. to everyone
Anonymous
I usually say "Dear Sir"...but Americans don't like "sir" (apparently):P
what is wrong with you
spamming, calling people Sir
Anonymous
"Sir" is quite common over here
18:07
yes, we've established that you're the poster child for Indian boys
Anonymous
At least I don't have an identity crisis.
@Blue absolutely not using that - he hasn't been knighted! :P
yep
that's like calling a random dude "Pope Smith"
like...wtf
if you're not a Pope, you're not a Pope
Anonymous
@0ßelö7 By the way you should revise the meaning of spam: "irrelevant or unsolicited messages sent over the Internet, typically to a large number of users, for the purposes of advertising, phishing, spreading malware, etc."
if you're not a knight, you're not a Sir
@Blue stop spamming pls
Anonymous
18:10
@Mithrandir24601 Hehe. I know that it's not common among the Westerners.
Anonymous
Here, professors get creeped out if you call them "Professor <Name>" or "Dr. <Name>". Quite the opposite.
@0ßelö7 "Dear Sir or Madam" is taught as the standard greeting to an unknown recipient in English here.
Anonymous
Same ^
Madam?
Anonymous
What's wrong with madam now?
18:13
Even when I have talked to someone who's knighted (or a Lord or Lady, which has actually happened) I still don't call them sir
Anonymous
@Mithrandir24601 You Brits are weird
Anonymous
:D
Ok I can map my ellipse to a circle
Not sure what happens now
@Mithrandir24601 I think "professor" is more common among undergrads, and "doctor" is more common among PhD students...
Professor is a stupid word, I never use it
Well, unless I am talking about "who is the professor for that class"
People who say "lecturer" (especially Germans) make me hate the universe
But then there are people who are not professors, just lecturers
So who knows
Anonymous
18:16
"Dr." is the stupidest imo. Someone who isn't a medical doctor shouldn't be called a doctor. :P
@Blue what?!
you're in the vast, vast, vast minority
VAST
@0ßelö7 Since "Professor" is an actual title and not just a job description in Germany, the distinction is rather relevant :P
Anonymous
@lılostafa Just my opinion
@ACuriousMind it's a title here too, but we don't make huge deals out of titles
thank you for making my point
Anonymous
18:17
PhD people should be given some other title
@0ßelö7 yeah, this is the thing - in the UK, we have research fellows, lecturers, senior lecturers and readers that aren't 'professors'
we do too
@0ßelö7 It is? I thought the American notion of "professor" is just whoever holds a job that's called "professor".
I just ignore all titles and call everyone Dr. unless corrected
Anonymous
I just call everyone sir or madam. Never had to be corrected. :P
18:19
@Blue Wait, what!! No!
@ACuriousMind Associate Professor, Assistant Professor, Research Professor, Adjunct Professor (?), Professor
these are distinct titles
No, they are jobs, not titles
what the fuck is the difference
clearly I do not comprehend the German notion of "title"
@0ßelö7 my title is currently 'Mr', but that's not my job
My job is a postgrad
@ACuriousMind are you telling me Germans will refer to someone as "Lecturer Horscht"
Anonymous
18:22
@ACuriousMind Actually "position" or "post" is the better term I think. All of them are professors but hold different posts.
(Or PhD student, if you prefer)
@0ßelö7 A title is something you commonly put in front of your name, and which you keep after the university (or some sort of royalty, in countries with formal remnants of aristocracy) has bestowed it upon you, regardless of your current occupation. You become a Professor after you pass your Habilitation, which is much like a PhD thesis and defense, and then you are Prof. Ryan Unger forever, regardless of whether you teach at a university or not.
Exactly like you don't lose your PhD degree if you stop working in the field
ok, we have no such thing
so Germany is just as bad as India, huh
@ACuriousMind Well, depending on the organization some may entail exactly the same jobs merely with differing levels of seniority.
@0ßelö7 That was my point when I said that the distinction between Professor and lecturer is actually relevant in Germany...
Anonymous
18:25
@0ßelö7 I think the same about America. ;)
In particular in many US institutions the 'assistant' and 'associate' modifiers just describe levels of (lacking) seniority. But 'adjunct' and 'research' usually do imply different duties.
@Blue America is 100% logical.
Anonymous
@0ßelö7 Loooooooooooooooooool. One word: DJT.
@Blue #MAGA
@Blue That's not a word.
18:26
@Blue can't even count
@ACuriousMind Yes. This is a significant cultural difference between Europe and the US. Long time professors in the US are generally granted the titles even after they retire as a social courtesy, but there is no rule that makes it a matter of law.
Anonymous
@0ßelö7 Tch mepls
And while we have a few even-more-snior-than-a-PhD degrees here and there there is no counterpart of habitation.
Anonymous
@0ßelö7 Ican'trdEng
18:29
Ironic that my two hardest classes are fluid mechanics
How do engineers do this? No joke, all engineers I know are awful at math, relatively speaking
Anonymous
@0ßelö7 You've been underestimating them. ;)
@DanielSank not available on libgen :(
This book is published only 23 days ago and there are already 6 used items available!
Anonymous
@lılostafa The Russians need some time to get their hands on it. Wait a month or two.
@lılostafa I have a book that I bought used on the day it was released...
saved \$30
@0ßelö7 ironic title
says basic number theory on the outside, does class field theory on the inside
18:38
@0ßelö7 Does that mean someone has actually bought and read it (or didnt like it) and decided to sell it again?
@0ßelö7 I've also just discovered that a UK professor is a higher position than a U.S. professor, which complicates things further...
...what does that even mean
Professor is the highest title modulo department politics
@lılostafa no idea
it looked unread
it was from one of those mass book resale places
@0ßelö7 It's apparently the same as 'distinguished professor'
(Or maybe they have somehow acquired a couple of copies at a lower price?)
@lılostafa I think that's it
I never buy from Amazon, but rather through the used links they provide
the books are usually new or almost new and are 1/2 the price
18:43
So, yeah, it's a bit political - a reader is essentially waiting on a 'chair' to become available to apply for a professorship
the only problem is that pubs like Springer don't always print their own books, so there will be slight variations from printer to printer
I have the doublet "Classical and Modern Fourier Analysis" by Grafakos, but one is a slightly different shade of yellow because they were printed by different people
I got this book for only $4 (real price was $352) just after it was published
There was only 1 copy available at this price, from Wiley itself at a book fair.
Wiley is a scummy publisher
they all are. Springer has some books for $200, but they have print-on-demand technology so I don't believe for a second that price is justified
Anonymous
The books are priced highly because the authors have to earn. Technical books are purchased by very few people compared to novels,magazines, etc.
I defer to @dmckee on book sale profits
@BalarkaSen are you proud of my drawing, sensei i.gyazo.com/01779e7130d1a1e3367d7df08b67d614.jpg
19:01
@Blue I hate it when people call a medical practitioner "doctor"
@0ßelö7 Add some finishing touches. Draw it like one of your French girls.
Anonymous
@lılostafa They are the real doctors though
@BalarkaSen Ok, here's my thought. The transformation $f(z)=z+r_0^2/z$ takes the $r_0$-disk to the plane with a branch cut (ignore that bit). But it takes the $R$-circle to the ellipse $$(R+r_0^2/R)\cos\theta + i(R-r_0^2/R)\sin\theta$$
Noun: doctor (plural doctors)
  1. A physician; a member of the medical profession; one who is trained and licensed to heal the sick. The final examination and qualification may award a doctor degree in which case the post-nominal letters are D.O., DPM, M.D., DMD, DDS, DPT, DC, Pharm.D., in the US or MBBS in the UK.
  2. If you still feel unwell tomorrow, see your doctor.
  3. Shakespeare
  4. By medicine life may be prolonged, yet death / Will seize the doctor too.
  5. A person who has attained a doctorate, such as a Ph.D. or Th.D. or one of many other terminal degrees conferred by a college or university.
  6. A veterinarian; a medical practitioner who treats...
so by tuning $R$ and $r_0$ I can take the holomorphic inverse and take the exterior of an $(a,b)$ ellipse into a disk with a certain radius
I need $a\ge b$ for this to work, I think
19:20
@Blue authors already earn from their main job :P Although I do want to know how much does actually go to the author
Anonymous
@Mithrandir24601 Why would person who earns well spend months/years to write a good technical book unless they paid well in return? As they say "no amount of money is enough" ;)
Anonymous
BTW, yes. The publishers do take a lot of the profit.
@Blue because they write the book as part of their job
because they want to write a book?
Anonymous
@Mithrandir24601 I don't think that's always true. It depends
19:23
@Blue maybe you should ask @dmckee
I do agree that they should get a reasonable amount, but textbook prices are often well above'reasonable'
he has said it amounts to no more than a few thousand for a very popular book
and a few hundred (if that) for so-so books
Anonymous
@0ßelö7 Huh, that sounds bad
@0ßelö7 I'm really not happy with that, as this suggests that the publisher takes an unfairly large chunk
@Mithrandir24601 I was talking about research monograph prices above. These books probably don't sell more than 50 a year
19:26
@Blue Because they want to share their knowledge. Just take a look at some of the excellent and free books that are out there (e.g. Hatcher's Algebraic Topology)
Sometimes they also just keep fleshing out lecture notes until it looks more like a book
Anonymous
@ACuriousMind Of course there are exceptions
Hatcher makes for an excellent monitor stand, btw.
@0ßelö7 Do you have actual furniture or do you just place everything on stacks of books? :D
@lılostafa you might want to delete that...
@ACuriousMind I have lots of furniture but books are very convenient!
19:29
@lılostafa ¯_(ツ)_/¯
@lılostafa hi could we pls not post links to NSFW stuff thank you very much
NVZ
NVZ
@ACuriousMind you lost an arm. ¯\_(ツ)_/¯
this fluid mechanics homework is impossible
where is tpg
@NVZ Yeah, ChatJax is eating it and I'm too lazy to escape it :P
Anonymous
Use \\
19:30
@Blue I just said I'm too lazy to do that.
NVZ
NVZ
@Blue you are lending a hand. so kind of you. :)
More lending an arm, I guess ;)
Anonymous
@ACuriousMind It takes more energy to type that reply than edit to add a "\" :P
@Blue I'm very particular about what sort of things I expend energy for ;P
NVZ
NVZ
oh, hey all. just popped up here at random. where am i? is the question in my head.
19:31
@ACuriousMind debate time
do I go to Costco today or tomorrow
@0ßelö7 Today, because shopping on Sundays is anathema.
@ACuriousMind ...how do you know that word
it's so obscure it's in the top 1% of Werriam-Webster lookups
@0ßelö7 By having had an education that included Latin and Ancient Greek :P
1 hour ago, by 0ßelö7
@Blue America is 100% logical.
@ACuriousMind In Tennessee we understand God's Love and know that He would want us to go to stores on Sunday.
Why is "Love" capitalized?
19:38
I thought Germans capitalized Nouns?
No, German capitalizes nouns, but a German speaking English doesn't :P
Anonymous
Even "store" is a noun.
Also, you didn't capitalize "stores"
Jinx @Blue
@ACuriousMind Typo.
@ACuriousMind Yes, but Germans use strange Words they call "Titles" so I think I will borrow their Conventions for spelling.
@0ßelö7 Spelling should also be capitalized, gerunds are nouns
19:40
Now, "spelling" might be a Noun there, but I am unsure.
@ACuriousMind I use the English convention of keeping Gerunds lower-case.
...does one have to capitalize Case there...
this is too hard
Anonymous
lolkek
I don't want to say every engineer is wrong, but I think every engineer is wrong
shouldn't $z+1/z$ map $0$ to $\infty$ and vice-versa?
The internet seems to be claiming otherwise
well, maybe not vice-versa. this is confusing
hmmmmm
I need a blunt
Smoking weed will not help your math skills ;P
Anonymous
@ACuriousMind @BalarkaSen wouldn't agree
@ACuriousMind complex numbers are too confusing, pls halp
OH MY GOD EUREKA
perfect example of homework helping understanding
I think I could build an airplane now
Anonymous
19:50
Microsoft Edge is trying so hard to persuade me to dump Chrome.
Anonymous
I wonder if I should give in.
@Blue it's one of two browsers than can play netflix in 1080p
Anonymous
What's the other?
Safari
Anonymous
I don't use netflix though
Anonymous
19:52
@0ßelö7 Ah...that fruit brand
@ACuriousMind so...you're an expert on holonomy now?
@ACuriousMind If yes, how would I go about computing $\mathrm{Hol}(S^n)$?
@0ßelö7 I don't think I've ever seen an actual computation of the holonomy group - you just apply Berger's classification
Anonymous
"This book was written for the “original” Arduino users: designers and artists. Therefore, it tries to explain things in a way that might drive some engineers crazy. Actually, one of them called the introductory chapters of the first draft “fluff”. That’s precisely the point. Let’s face it: most engineers aren’t able to explain what they do to another engineer, let alone a regular human being. Let’s now delve deep into the fluff." Bwahaha...sweet revenge.
@ACuriousMind Well how did that guy do it?
@0ßelö7 I think that might have involved doing something like that computation for the sphere, but I don't know actually
19:59
@ACuriousMind I am reading Berger's book and he tells the reader to do it as an easy exercise :/
"for a generic Riemannian manifold Hol_0 =SO(n)"
what the heck does generic mean there
@0ßelö7 One without special features like being Ricci-flat
@ACuriousMind "without special features" seems like an awful definition!
how is one supposed to know which special features it has
I think in this case it means "not locally a product space, not a symmetric space, not Ricci-flat, not Kähler, not Einstein" :P
At least these are all the conditions for special holonomy I can think of off the top of my head
He uses the Ambrose-Singer theorem, which is cheating
Is $\exp \mathfrak so(n)=\mathrm {SO}(n)$?
I would believe it since SO is connected
@Blue originally the title was an academic one at a time when physicians in Europe were barely more than folklore equipped leech mongers. The medical community eventually established schools and worked very hard to get the title applied to their practitioners.
So the common usage these days represents an interesting inversion of meaning.
Anonymous
20:07
@dmckee Interesting...didn't know that
So start referring to physicians as "leech mongers"
As for textbooks you write one (a) to fill a need that you perceive, (b) for the pure self-satisfaction, (c) because it will make your case for tenure, promotion, a raise or whatnot with your colleagues or (d) ... I'm not actually sure why else, but people being people I'm sure there are other reasons.
Anonymous
@0ßelö7 Sure. And will also call mathematicians as philosophers. :P
@ACuriousMind uh, really, if I know that Lie(Hol_0) contains all of so(n), can I conclude it is SO(n)?
@Blue no skin off my back, I'm not either
@0ßelö7 Yes, I think so
20:13
@ACuriousMind I guess the point is that each element of SO(n) is contained in a one-parameter subgroup containing the identity?
Seems very reasonable
Just take the rotation angle --> 0
@0ßelö7 Aye
ok, back to fluids
@0ßelö7 and I thought I loathed astro fluid dynamics...
@Mithrandir24601 did you have to do what I'm doing
I have to find a flow over an elliptical cylinder that produces a generic lift of F newtons
I have NO idea what I'm doing and I lost the paper I was reading about it ;_;
20:29
@0ßelö7 not like that no... Astro was very specific to, well... astro physics... I did do 'regular' fluid dynamics in 2nd year though
dynamics or statics?
I'm not sure this particular problem could be done in 2nd year, you need complex analysis, which is making my brain hurt
not the complex analysis, but these conformal mappings
I have no intuition
@0ßelö7 this is what astro fluids feels like :/
@ACuriousMind Is the 1-point compactification compatible with the smooth structure, i.e. is there a unique way to turn the compactification into a smooth manifold?
It never improves with time
Anonymous
@Mithrandir24601 Is it because the professor didn't bother to teach the intuition behind the topics or is it actually tough to develop an intuitive sense for astro fluids?
20:35
@0ßelö7 1-pt cptfication of a manifold need not be a manifold
@0ßelö7 I have no idea but I suspect not since the existence of exotic 4-spheres is an open question but there definitely are exotic $\mathbb{R}^4$s.
@Blue I'm just a failure (literally) at astro fluids
@ACuriousMind hmm
Anonymous
@Mithrandir24601 Umm...did you ever analyze why ?
@Mithrandir24601 you failed the course?
@BalarkaSen classical paper in physics link.springer.com/content/pdf/10.1007%2FBFb0070611.pdf
Anonymous
20:38
I'm asking because I'll be taking a fluids course next year
@0ßelö7 by 1%, yeah
@0ßelö7 Very noice
Love the PDEs
public display of equations
@BalarkaSen I'm looking for reasons anyone should care about heat kernels
@Blue I hated the lectures and the lecturer, so none of it ever made sense. Also, I was an idiot and revised the night before. The thing I revised naturally came up, but of course I forgot it as a result of revising it the night before
20:40
@Blue my university offers a dozen fluids classes from various departments. It's completely variable
I'm taking two right now. One from math and one from nuclear engineering
there's a graduate one in nuclear engineering where they derive all of the horrible models you use in a first course
Anonymous
At the undergraduate level it is only offered by the Mechanical department, over here. At the graduate level I think even the Math and Physics departments offers it.
@Blue oh, bog standard fluid dynamics was fine, it was just astro fluids that was the problem
like the shear stress over a flat plate. I want to take it
@Blue do you not have an aerospace department?
Anonymous
@Mithrandir24601 I see. Relief. However, "astro fluid dynamics" sounds cool
Anonymous
@0ßelö7 No
20:44
Ah, well there's your problem
Aerospace will have too much fluids for any sane person
@Blue it was awful
@BalarkaSen Lol, the ice is assumed to be at 0K
"We give several examples where reasonable physical intuition
is dead wrong. "
:)
"Formulas are smarter than people."
@BalarkaSen I found my senior thesis quote
Anonymous
@0ßelö7 There are hardly any jobs for aerospace engineers over here. Very few unis offer that stream.
@0ßelö7 I always go with the "this [result arising from a clearly ridiculous list of assumptions] was shown to be wrong several decades ago"
Anonymous
Those who are interested in aerospace usually shift from Mechanical to Aero during their MTech
Anonymous
20:53
@Mithrandir24601 I c..hehe :P
Anonymous
:D
Anonymous
@0ßelö7 There are some weird engineering courses in Indian colleges, like: "food engineering", "ink and printing engineering", "paint engineering", "petroleum engineering". I've no idea how they can be called engineers...
petroleum engineering is a vast and important field of engineering
Anonymous
That sounds like a sub-stream of chemical
21:01
@Blue no
you need to get the stuff out of the ground
and keep the locals away from the pipeline
it's an art
@Blue Don't you just love the petrol smell?
For petroleum refinery engineering, see Process engineering. Petroleum engineering is a field of engineering concerned with the activities related to the production of hydrocarbons, which can be either crude oil or natural gas. Exploration and Production are deemed to fall within the upstream sector of the oil and gas industry. Exploration, by earth scientists, and petroleum engineering are the oil and gas industry's two main subsurface disciplines, which focus on maximizing economic recovery of hydrocarbons from subsurface reservoirs. Petroleum geology and geophysics focus on provision of a static...
Anonymous
I wouldn't like to spend 4 years studying about petroleum...lol
@Blue I wouldn't want to spend 4 years studying electricity
> Since any question about constant coefficient second
order ordinary differential equations must be trivial
this is left as an exercise.
@Blue There's also Reservoir engineering, Drilling engineering, Production engineering, ....
21:05
Textile engineering
Anonymous
@lılostafa goddamit..I'd suffocate out of boredom
@Blue sewer engineering...oops
Textile engineering teaches you how to be a technically-minded tailor
@Avantgarde you jest but I imagine making good winter jackets is nontrivial
especially making them affordably
@Blue I remember a faculty member (of some university here) saying they were once asked to start "cosmological engineering" :)
21:07
I agree with that
Did they?
that sounds like something sufficiently useless that @Blue would like it
Astrological engineering
@Avantgarde No :)
Anonymous
Tbh I've started to respect the people like carpenters, electricians, etc...more now. After a few carpentry classes I realize how difficult it can be to cut and shape wood properly to make furniture.
Anonymous
@Avantgarde That's the best
21:09
you didn't respect electricians???
Anonymous
@0ßelö7 "more"
And cooks/chefs, @Blue
Anonymous
Yeah, that too^
How do you download videos from YouTube?
Anonymous
Good chefs are rare
21:10
but not people who make forks/spoons :/
@lılostafa go to one of the billion sites that do that
there are also browser plugins
Anonymous
@lılostafa tubemate
@lılostafa Wanna start a Knorkator archive? :P
@Blue sounds like a porn service
@Blue Working with metal/wooden lathe?
Anonymous
@0ßelö7 You seem to be quite knowledgeable about such services
Anonymous
21:13
@Avantgarde Lol...you're stretching it now
@Blue Huh? I thought you meant that's what you were doing.
@Blue Wow
@Blue My father works as an operator of metal lathes, careful :P
Anonymous
Phew. I agree. :P I think I have highest respect for "sewer workers". Nothing can beat that.
Feb 8 '16 at 3:28, by ACuriousMind
When I was four I wanted to be a garbage man because they get to ride on the garbage truck. Yeah, I don't know what I was thinking, either.
21:17
sewer engineering
@ACuriousMind Chris White was there :(
@ACuriousMind no
@ACuriousMind do you understand Brownian motion?
@0ßelö7 No
@lılostafa :'(
@ACuriousMind did you see the link (before the edit)?
21:21
@lılostafa Yes (you know the edit history is accessible to all, right? :P)
@ACuriousMind it seems nontrivial
@0ßelö7 :'(
@0ßelö7 "it" = "Brownian motion"?
@ACuriousMind Yeah. To understand crushed ice I must first understand Brownian motion on manifolds
Are you trying to make the mathematically perfect drink or why are you trying to understand crushed ice?
@ACuriousMind I'm a fan of thermodynamics on manifolds
21:25
Ewwwwwwwwww
@ACuriousMind did you not read those slides I sent you?
it was thermo...
Ah, well, I guess the heat equation is technically thermo...
Still you could be mathematically interested in the heat equation without liking thermo :P
I just use "thermo" as code for "stuff involving heat equations and Laplacians"
Ricci flow is also just thermodynamics
also, to understand the spectral effects of attaching thin handles to manifolds one must understand Brownian motion
I don't know why, as of now
@ACuriousMind Geometry is very physical. Understanding topological perturbations of spectra is related to studying heat flow under an appreciable modification of the object
in other words, it's GDP
Ewwwwwwwwww
2
@0ßelö7 Gross domestic product?
21:33
yes
@ACuriousMind I think this is just Wiener measure. Do you understand that?
@0ßelö7 I know that Brownian motion is related to the Wiener measure, but I'm not sure how one can "understand" the Wiener measure
I should find a blue ninja suit to match ocelot's green ninja suit, lol.
@ACuriousMind seriously, WTF?! WTF?!!
> See [14] for the version stated above
> [14] Glimm and Jaffe
Oh NOOOOOOOO it's come full circle
@lılostafa I have a feeling you simply don't appreciate their kind of humor :)
21:38
@ACuriousMind Have you read Grimlock and Jeffree? It seems quite technical
@0ßelö7 I have "read" it but I won't claim to have worked through all the details
For me, it's not thermo without entropy
(thermo != thermal)
@Semiclassical Perelman's proof of Poincare Conjecture is all about entropy
@ACuriousMind That guy is funny as hell but in a really strange way
21:43
Hey Semi is here too.
@lılostafa That's...a very accurate description :D
@Semiclassical Understanding how the entropy evolves with the flow, changes under surgery, etc.
fair enough.
And the entropy is based on string theory Lagrangians
21:44
well, there's also a logarithm
Has anyone here actually bought a copy of Shankar's Fundamentals of Physics I and II?
It has such good reviews on Amazon and people compare it to the Feynman Lectures.
@Semiclassical one of the entropies is just $\int u\ln u \,d\mu(g(t))$
@0ßelö7 Sorry, but I don't understand what it has got to do with GDP. =)
then there's $\int (|du|^2/u +Ru)\, d\mu(g(t))$, which doesn't seem like entropy
@Jasper thermodynamics is one of the pillars of the GDP
LOL
21:50
why is that funny?
Well, I find many things funny, because I have a funny mind.
@ACuriousMind Huh, this old paper calls the trace of a matrix spur, in English!
@0ßelö7 I feel like I've seen that before.
@0ßelö7 hah, googling gives this example: books.google.com/…
some rather inconclusive discussion of Spur is here: math.stackexchange.com/questions/1291981/…
22:04
@Semiclassical Hmm. This paper is written by "McKeen" and "Singer" in 1967. The first one is either American or Irish, the second could be German.
terminology is weird sometimes.
But 1967 seems pretty late for still using German linear algebra terminology, and if that MSE post is to be believed, "spur" came after "trace".
22:21
@vzn FWIW 50 links / 250 days seems very reasonable to me.
can someone tldr the method of reflections for me?
22:50
@ACuriousMind Suppose I have a manifold with boundary $M$, and take its double $V$. Is the map $r:V\to V$, which takes a point into its "opposite", a smooth map?
I fear something goes wrong at the boundary
Nah, cuz in an appropriate boundary chart, it's just $x\mapsto -x$
23:27
Is there a recommended program for making geometric diagrams to include in answers?
23:50
@simplicio In all honestly anything that you know well is better than struggling with a 'perfect' but unfamiliar tool.
2
I tend to use root for histograms and other graphs and tikz (a LaTeX package notorious for nasty and opaque syntax) for certain classes of line drawing. I also own a Wacom tablet and can, in principle, draw free-hand figures when needed.
But both root and tikz are not things that you would learn for that purpose: they are tools I know anyway.
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