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10:00 PM
But I think those two are pretty harmless.
 
As opposed to me, you mean? :D
 
It's 6 am here, and my mum just woke up.
Sorry, I like to announce trivia in this chat.
 
well, civilized people do awaken at 6 or 7 am, @Jasper ... only undergraduate and graduate students think that's the night.
wb @RobertCardona
 
@TedShifrin It is not the night. For me it is the end of the evening :p
 
@TedShifrin Well, she is going to work to support her mentally ill son. I feel really bad.
 
10:02 PM
Well, @Jasper, I hope you do everything you can to help her ... cleaning, cooking, etc.
 
what is a word for something where there's always a bunch of stagnant water in the bottom
 
Why the welcome? :P
 
Should I retract it, @RobertCardona?
cesspool, @Alex?
 
@TedShifrin that's the one, thanks.
 
nope!
just curious if there was any particular reason.
 
10:03 PM
You are being unusually cruel to @BalarkaSen professor @TedShifrin may I ask why?
 
Nope @Ted. The rest of the crew is still working.
 
LOL, @skull, you may ask, but I needn't reply.
Damn, @Mike, they are slow.
 
@TedShifrin Anyway, I really hope to start studying math on New Year's Day. After that, all my plans will follow, hopefully.
 
I hope so, @Jasper, and I even hope to answer some questions you pose once in a while.
 
@TedShifrin It is unlikely, but I hope to answer some of your questions one day, lol.
 
10:05 PM
@skull: He has his charms, but he has the arrogance of someone your age, and there were several instances where I just got fed up.
 
@Ted I'm told I'll be able to look at my evals late tonight.
 
@Mike: We don't get to see evals until the grade submission deadline. That is as it should be.
 
@Ted We don't see evals until grades are submitted. That's what I meant.
 
Oh wait, I don't know what @skull's age is. ... of someone half my age, I mean.
Oh, here it's universal, not person by person, @Mike.
 
@TedShifrin I suspect skull is around 50.
 
Huy
10:06 PM
Good evening everyone.
 
well, maybe not quite that old, then.
hi @Huy ... Es geht beßer?
 
Huy
Ja, aber ich bin müde.
 
@TedShifrin So when was the last time you talked to Lee?
 
@TedShifrin, I see you work in Complex Algebraic Geometry, do you use much K-Theory?
 
@RobertCardona You should be warned that K-theory can mean a number of things.
 
10:10 PM
I learnt that there is L-theory as well.
 
no, @RobertCardona, never. I was more on the classical geometric sides of things :)
 
I suppose Algebraic/Complex K-Theory
 
@Jasper: Aside from comments exchanged on here, I saw him in person about two years ago, I think.
If I actually retire to CA, I plan to visit Seattle. I have a lot of friends there.
 
I don't think complex K-theory's a thing (unless you mean complex topological K-theory), @RobertCardona. Usually one speaks of albebraic, topological, or operator K-theory, all related but definitely distinct.
 
@Mike's on his phone again :P
 
10:12 PM
(I dunno anything about algebraic K-theory.)
Usually am @Ted
 
I don't know anything about K-theory, except that it starts with K.
 
Huy
@TedShifrin: I have two exams coming up, in General Relativity and Differential Geometry (in that order) with a break of a week in between. Usually, I study last for the first exam, but I'm a bit scared because it's quite a lot for General Relativity. How did you use to study?
 
I took a course in generalized cohomology theories in grad school, but it wasn't all that of interest to me. That was almost 40 years ago. Sigh.
I never studied, @Huy :P
 
Huy
@TedShifrin: :o ??
 
My bad, I meant complex topological K-Theory :P I saw a book on that a while back and just remembered "complex" and "k-theory"
 
10:13 PM
But those two are quite allied, so that's interesting. What sort of stuff in diff geo?
 
Breakfast time, later.
 
bye @Jasper
 
Ah, yeah. That means you're studying complex vector bundles on spaces. (There's a bit more to it than that, but that's the gist.)
 
I have a copy of Atiyah's K-Theory, but it doesn't have any exercises :/, I'm pretty sure that would fall under the category of Topological K-Theory
 
A connected planar graph has 26 faces and V vertices, and all its vertices have the same degree. What are all possible values of V? What I have so far: V + F = E + 2 . -> V + 26 = E + 2. V-E = -24. What do I do next?
 
Huy
10:15 PM
@TedShifrin: We hardly covered anything (compared to usual diff geo courses). We did some immersions and submersion, Lie stuff, Riemannien metric, geodesics, tensor and vector bundles, Riemannian curvature, second fundamental form, etc. Those are the things I can remember just off the top of my head. The prof who held the diff geo lecture is well known for being the slowest lecturer in the whole maths department
 
I think Weibel's K-book is now the canonical source on algebraic K-theory, but (for its motivating examples), it assumes you know a chunk of algebraic topology, IIRC.
 
LOL, @Huy. I think that's the opposite of my 36-year reputation :P
 
That doesn't sound like barely anything @Huy
 
Did you prove Cartan-Hadamard, @Huy?
 
If you challenge his mathematical ability Professor @TedShifrin I'm sure his arrogance will disappear this time, I believe he has learned his lesson.
 
10:16 PM
Homogeneous/symmetric spaces?
 
Huy
@TedShifrin: I'm not sure actually because I missed a lot of classes because they took place during my linear algebra tutoring classes. I'll have to check.
 
What exercises/proofs are you studying for the exam, @Huy? I can give you an exam :P
 
Huy
@TedShifrin: math.ethz.ch/education/bachelor/lectures/hs2014/math/… This is the latest exercise sheet. I didn't study the exercise sheets yet.
 
Ah, I've given stuff about the Lie bracket for parking, before :P I usually assign this stuff early in the course. Weird.
I won't meddle, @Huy, but if you have good questions, let me know.
 
@MikeMiller, thanks. I'll look into it. I'm about to get started on Magurn's "An Algebraic Introduction to K-Theory", but will keep Weibel's book in mind!
 
Huy
10:19 PM
Hm. I have no idea how well the exercises were synched to the lecture.
 
Sounds like you didn't take the course, @Huy :D
 
LOL. "Why is parking so difficult"
 
@Mike: If I sent you all my exercises, there's the Lie bracket exercise on how to park.
 
Huy
@TedShifrin: I am not a fan of lectures. Also, as I said, two of the four lectures took place during my TA class, so I couldn't attend them. And by the end of the semester, I focused on different things so I couldn't attend the other two anymore either.
 
@RobertCardona Hope you enjoy it! Like I said, I dunno anything about algebraic K-theory, so I can't say anything about those books.
 
Huy
10:20 PM
@TedShifrin: How do I recognise a good question? :D
 
Well, @Huy, in my grad diff geo course, I follow no text, so pretty much the students need to come to lectures if they expect to learn :P
Years of experience, @Huy.
 
I see you like D-modules. Can you tell me what their deal is?
 
Oh, you changed.
 
Huy
@TedShifrin: I just used the copy machine. :D
 
Differential equations + module theory, @Mike.
I'll tell you if the question isn't worth my time, @Huy :D
 
Huy
10:21 PM
@TedShifrin: How do I show x^2 is not injective ?????
 
Go away.
 
Huy
(please full solutions only)
 
I know what a D-module is, @Ted, but that's hardly sufficient. I'm curious what the point is, the interesting questions, how stuff's studied...
 
I could have told you more 30 years ago, @Mike, but now I'm mum.
 
Huy
@TedShifrin: So how come you never studied? Are you a genius?
 
10:22 PM
We offered a course on 'em last year. Probably this year too. I doubt I'll attend, though.
 
I was given a book on the subject and told I would like it, but haven't gotten around to it. That list is more of a list of things I'm studying or going to study :P
 
If one works throughout the year there's not really a need for studying... at least, in my experience.
Oh, I see @RobertCardona
 
Huy
@MikeMiller: I did work hard throughout one of my semesters, but still had to study because I didn't manage to keep up with every subject all the time. And, just to be sure.
 
When I have a better answer to your question, I'll be sure to ping you.
 
Thanks, @RobertCardona!
 
10:25 PM
@Huy: I certainly studied, but that was basically 40 years ago :P
 
Huy
@TedShifrin: Did you study GR?
 
nope, I've only encountered a tiny bit.
 
Huy
Most physicists told me it's the most beautiful subject they've ever come across. But I don't see it yet. Also, they're physicists, so you never know.
 
How about QM?
 
Dirty physicists.
 
10:27 PM
I would wager that most physicists don't even know GR.
QM is much more universal.
 
Huy
@skullpatrol: They did QM. QM isn't that beautiful. It has some very nice solutions of problems, but I don't think much of it is really beautiful.
@TedShifrin: Obviously those statements about GR were made by physicists who actually took GR.
 
What about string theory?
 
And QED?
 
Huy
@TedShifrin: There was a course about String Theory this semester but unfortunately I didn't dare to enrol, given that I hardly managed to visit any other lectures...
@skullpatrol: I never studied QED.
 
yeah, String Theory is serious physics + almost all parts of math.
 
10:29 PM
String theory is physics, @Ted?
 
theoretical physics, @Mike, albeit.
 
If it can't make testable predictions, it's not fair to call it science.
 
Huy
@TedShifrin: You know, if there was no such thing such as responsibility and necessity to earn money, I would much rather just visit lots and lots of lectures, because there are so many awesome lectures at my uni but I can't visit them all due to time shortage. That makes me sad.
 
Indeed, @Huy. I can't believe you're teaching high school and trying to take serious graduate courses.
 
Huy
@TedShifrin: I also TA'd for linear algebra this semester. But I didn't apply for next semester. That was just way too much work.
@TedShifrin: A lot of more mathematical CS stuff also really interests me, such as cryptography or complexity.
But I doubt I will ever have time to properly study it.
 
10:31 PM
well, crypto is serious number theory, plus CS
 
@Huy Talk about it in here
 
Huy
A friend of mine asked me to go to cryptography lectures with him because he doesn't want to go alone.
 
Those are the things that I like.
 
is that like going to a strange bar? @Huy?
 
Huy
@AlexanderGruber: I know hardly anything about them. I had a course about algorithms and complexity, and the first part about algorithms I hated everything, but the complexity part was rather interesting.
@TedShifrin: Apparently, for him.
 
10:32 PM
I get it. Cryptographers are scary.
 
Huy
@AlexanderGruber: Also there's more women in a CS class than in an engineering class, at my uni. So maybe that scares him.
 
Hell, most math people are scary.
LOL @Huy
 
Most disciplines seem to have a personality type, in my experience crypto guys tend to be really quick witted and like to jump all over you.
 
Huy
@AlexanderGruber: Is that how you would characterise yourself then?
 
That's not necessary and sufficient, @Alex ... I'm no cryptographer.
 
10:34 PM
@Huy Nah, but who can characterize themselves? Maybe I do it without knowing it
 
Does anybody know how to resolve resistances in a circuit?
Using Kirchoff and linear algebra
 
Huy
@Alizter: Do you mean theoretically or in practice?
 
@Alizter assimilate them into your cube
 
Theoretically
 
Huy
@Alizter: Use complex numbers and everything will be 1000x easier.
 
10:35 PM
You mean a system of linear equations, @Alizter? Not rocket science.
 
@Studentmath are you online currently?
 
Huy
@Alizter: You literally only have to look what the circuit consists of and then pick the right formula and solve it for your desired variable.
 
@TedShifrin More how to form the system from the circuit
 
@Huy do you know much algebra?
 
I have examples of that in my linear algebra book, @Alizter.
 
Huy
10:37 PM
@AlexanderGruber: I loved linear algebra. I didn't understand much of abstract algebra, however my best mark so far was in abstract algebra. So I guess I just understood more than most other students.
 
@Huy did you guys get to finite fields?
 
Let me draw up the circuit
 
Huy
@AlexanderGruber: Yes. I also took an extra course about finite fields, however never took the exam. It was rather interesting though. We did some sort of sudoku. It was called magic something.
 
@Studentmath Do you remember for the problem I asked you about, where there were 5 vertices, and I had to find how many ways edges can be drawn between pairs of vertices (since it is a simple graph) such that the graph was connected? And I also had to find it for 4, 5, 6 edges? That was what I was referring to.
 
Ahhh cool
 
10:38 PM
magic squares, @Huy
Indeed an application of finite fields.
 
Huy
@AlexanderGruber: We called them Latin squares?
Is that the correct translation?
 
oh, Latin squares, sorry ...
yes, @Huy
 
Huy
Why sorry?
 
this is a really cool cryptosystem I was studying earlier this semester you might be interested in @Huy
 
I said magic squares ... maybe they're the same ... now I've forgotten
 
Huy
10:39 PM
@AlexanderGruber: I'm sure I would be interested in but I think if I have time to study something I should focus on my exams right now. And after that I have to study game theory in order to prepare a course at high school about it. =_=
 
Well, what you call them is just a matter of definition, lol.
 
I'm not expecting you to read all that (unless youre interested of course) but the schematic is outlined on page 15
@Huy Sure- no prob
 
I can call a cat a dog and a dog a cat, said one of my profs, lol.
 
Huy
@AlexanderGruber, @TedShifrin: You don't know by any chance if any MSE chatroom regular is an expert in game theory?
 
If you end up wanting the link again sometime just ping me, I haven't posted this publicly yet cause there are a couple calculation details I wanted to make sure were right
 
10:41 PM
So you learned about equivalence relations, @Jasper?
 
@Huy There are none.
 
No, @Huy, sorry. I'm certainly not.
 
@Huy I have taken several courses about it
 
Huy
@AlexanderGruber: Thanks, I will.
 
10:41 PM
So how can I find the total resistance?
 
I wouldn't say I'm an expert, but there's a chance I will know what you're talking about
 
@Huy You really should ask me about chat matters, because I am the chat expert, lol.
 
I tried to apply Kirchoffs by drawing in some current flows
I only managed to get 3 equations
out of 5 variables
 
Huy
@AlexanderGruber: I won't need to go into too much depth. I just need to know enough to being able to present stuff to my high schoolers and create new problems.
 
@Alizter I think this is the wrong room, lol.
 
10:42 PM
@JasperLoy Why? It's just linear algebra
 
Huy
@JasperLoy: Okay, I have a question. When was the last time you were not in this chatroom for more than 72 hours?
 
@Huy Oh yeah, I definitely know that much
 
Did you use both of Kirchhoff's laws, @Alizter?
 
@Alizter Well, we don't know the physics, lol.
@Huy I don't know, lol.
 
Speak for yourself, @Alizter. This is not advanced physics.
 
10:43 PM
@TedShifrin There are two?
 
Huy
@JasperLoy: Don't you do that kind of stuff in high school, in physics?
 
LOL, yes, @Alizter :)
 
@TedShifrin I know Kirchoff's law as current in = current out
 
@Huy Yes, but I have forgotten all my physics.
 
what is the other one?
 
10:43 PM
And around any closed loop, net voltage drop is $0$.
 
Huy
@JasperLoy: That's a pity, imo. Some of it can be really cool, actually.
 
@Huy In fact, I have forgotten all my math as well. But once I start studying, I will be back in shape again, lol.
 
oh ok and then with ohms law
ah
 
right, @Alizter
 
Huy
@JasperLoy: I hope so, for you.
 
10:44 PM
that makes 5
 
That'll give you your extra equations.
 
Thank you @TedShifrin
 
You're most welcome.
 
This is the problem with learning on my own
 
@Huy Anyway next time before you decide to give a course on topic x, make sure you already know topic x.
 
10:45 PM
People who skip classes have the same problem, @Alizter :P
@Jasper: It's my fault. I suggested game theory as being of broad interest.
 
@Alizter I really think you need to get a textbook. Just get the one closest to your syllabus.
 
@TedShifrin I will not have these classes for a long time
 
Huy
@TedShifrin: math.ethz.ch/education/bachelor/lectures/hs2013/math/… How about these exercises?
 
@JasperLoy My syllabus does not even mention Kirchof
This is physics I am learning for myself
 
@Alizter I would think Kirchoff's laws should be in A level physics. They were a decade ago.
 
10:46 PM
@JasperLoy We have 'advanced' ohms law problems
 
@Huy: Total mixed bag. Some would be at the beginning of my graduate course, some would be at the end of my undergraduate, and others would be in the middle of my grad course. Weird.
 
Huy
(I love this part: "Exercise 1.12. The following question, though fun, is not examinable.")
 
@Alizter Check out the CUP website for all the A level books they publish. They're all good.
 
Huy
@TedShifrin: This set is part review
I overread that.
 
I just saw that.
 
10:47 PM
I might rummage through my dads books to see if there is a text
 
@Huy jesus i must not remember much game theory
 
@Alizter OK. But those would probably be ancient.
 
Are you doing a coherent linear algebra curriculum, @Alizter?
Ancient is not necessarily bad.
 
Huy
@TedShifrin: I just opened the homework assignment with the largest count number. But then, number 12 would be this: math.ethz.ch/education/bachelor/lectures/hs2013/math/… It's from last year's diff geo course, btw.
 
@TedShifrin What do you mean by coherent?
 
10:48 PM
Even Cambridge doesn't have a course in game theory in its 3 year course.
 
Huy
@AlexanderGruber: How so?
 
As in following a standard curriculum, @Alizter?
 
@TedShifrin Well I don't study this stuff yet so I don't know
 
That's more sophisticated, @Huy.
 
Huy
@JasperLoy: The topics I know are either too boring or too advanced for high schoolers. I myself find Game theory interesting, so I figured why not.
 
10:49 PM
@Huy I was just playing. pretending I thought the diffgeo was game theory
 
Where are you studying it, @Alizter?
 
@Alizter Also, I really think 5 subjects is too much, consider dropping 1.
 
The standard at uni is too unpredictable because I do not know where I will be going
 
Huy
@AlexanderGruber: I almost thought you actually meant it.
 
@Huy Aha! I heard all about it, but I just ain't interested in playing any games.
 
10:50 PM
@JasperLoy If I tell my school I want to drop a subject they will make me drop physics
 
It's not just playing games, @Jasper, seriously.
 
Game theory is actually very difficult I hear
 
@TedShifrin OK. Like economics and so on.
 
research stuff anyway
 
Huy
@JasperLoy: You'll also get gorgeous women, as you saw in "A Beautiful Mind". It's a true story.
 
10:51 PM
yes, and political science, too, @Jasper.
 
@Huy Well, the story in the movie is not the same as the real story though.
 
@Alizter once you put in real-deal probability i bet it gets monstrous
There is already some pretty hard combinatorial problems even in discrete game theory i think
 
Huy
@JasperLoy: NO??? But..... Why not???
@TedShifrin: May I ask at what age did you become a professor?
 
@Huy Did you read the book? The book has the real story. There are many differences.
 
@Huy: Postdoc starting 26, assistant professor starting 28.
 
Huy
10:52 PM
@JasperLoy: I didn't read many books previously.
@TedShifrin: They are always so young.
 
@Huy The real story is not as beautiful as the movie. Nash had a child with another woman, for one.
 
Well, that's what happens when we go college->grad school without a break.
 
....some of us.
 
The movie was a sham, @Jasper.
 
10:53 PM
Sorry, @Alex. I didn't mean to impugn you :P
 
Nonetheless, the movie still inspires.
 
It totally hid what I believe was a serious part of his mental issues.
 
That's what movies do. They are not meant to be totally accurate representations of reality.
 
Nah I'm just playing. I took the very scenic route through undergrad.
 
Totally clear in the book.
 
10:54 PM
Art imitates life and life imitates art.
 
Huy
What is actually correct about the movie?
 
Well, when they pretend to be, it annoys me.
 
@TedShifrin The homo part?
 
Yes, @Jasper, the homo part.
I think that was a serious part of his issues.
 
@TedShifrin Only Nash himself will know, but I believe that the homo part wasn't a big part of his mental illness.
 
10:55 PM
Well, obviously, I didn't ask him when I met him.
 
Also, I am not exactly sure he is homo.
 
Oh wow I didn't know about that.
 
But, based on my experience with lots of students, I totally disagree with you.
 
I can be hetero and like guys too sometimes, you know.
 
Well, you can say you're hetero ...
 
10:56 PM
What I mean is that it is a spectrum.
 
I would really prefer you didn't say homo. It's still considered (and used as) a slur.
 
I'm well aware of the jargon.
 
And nobody is at the ends of the spectrum.
 
That's wrong, too.
 
Oh well, you know what I mean.
 
Huy
10:57 PM
Is it considered a slur in the US?
 
Yes, @Huy
 
Huy
It is rather common here, not very slur.
 
Oh, I use it as an abbrev, just like Jap, which I now know is considered offensive.
 
Yes, that too is very offensive
 
Huy
*Jasp
 
10:57 PM
Not many people in my country know that Jap is offensive.
 
you gonna say kike next?
 
I dunno what that is.
 
Huy
I didn't either, until I just looked it up.
 
LOL
 
Is it a kite?
 
Huy
10:58 PM
My mother will be very angry to learn that internet strangers are teaching me swear words, @TedShifrin
 
not swear words, @Huy
 
@JasperLoy Does your language usually borrow abbreviate when it borrows words from other languages?
 
Wow, I ask people to not use slurs and it just leads them to say more!
Suppose that's the way of things.
 
there's a lesson in there somewhere, @Mike
3
I've gotten into some scenes in here before, btw
 
@AlexanderGruber I don't know. I speak English here too, lol. And also Chinese.
 
10:59 PM
I'm not gonna dig for it, @Ted
 

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