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10:07 PM
@robjohn Can I ask a question? If no: Nevermind. If yes: Why do we take a cone in the maximal function and say not a parabolic one. I haven't tried to see what happens.
 
@Srivatsan There's quite a rush of these elementary formal logic questions, though.
 
@HenningMakholm I guess the lecturer would be happy to know that this site is becoming popular among the students of the course...
2
 
10:23 PM
Well, I think they should eventually adapt their ways of grading people. You can't stop people from checking the internet.
But then. They. should. at. least. try. to. ask. proper. questions!
 
@JonasTeuwen You're certainly not the first to have observed this.
 
No of course not. I'm not claiming any originality.
 
@JonasTeuwen I don't think that's the main problem. But clearly some people, somewhere, are in dire need of a short quest lecture on How To Ask Homework Questions The Smart Way On The Internet.
The only question is, how do we find out which course where?
 
Right. I don't care that they cheat. It will bite back eventually. But they should ask good questions :-).
 
And do we have one amoung our illustrious number within easily traveling distance of that school?
 
10:29 PM
Wow, I didn't notice the great starred comment by Rob!
 
(My copy of Underwood Dudley's Mathematical Cranks arrived the other day. So far it's been a more immediately enjoyable read than Kunen's set theory textbook from the same shipment.)
(Don't know what suddenly reminded me of this...)
 
@Potato It's easy - just orthogonalize the two vectors to get from w1, w2 a new orthogonal base w1,w2'.
For orthogonal base your argument works: just take neighborhood of 0 with radius 1/2*min(|w1|,|w2'|).
 
@Martin, one has to be quick to converse with you!
 
I thought that when I choose reply, chat will add ping for Potato authomatically.
That's why I deleted it and posted again.
 
@HenningMakholm What is it about?
@MartinSleziak But you can also edit the message, right?
 
10:34 PM
Right.
I will learn to use chat here... eventually.
 
@JonasTeuwen Dudley's book? Exactly what it says on the tin.
 
Then it must be great. Let me see how much it costs.
 
@JonasTeuwen I think that JDH's answer in the thread I linked to above summarizes my opinion on that pretty well.
@MartinSleziak The ping worked from the beginning. The problem is that chat has some problems with multi-line messages. See here (and the messages below and above that for more)
 
Thanks
 
@tb I agree with that post. But sometimes I don't really feel like supplying all details as they should be able to fill them in if they got that far already. That probably amounts to a "bad answer" in JDH-speech.
 
10:41 PM
Heck, sometimes I don't like working out all details if I can just say, "clearly this can be rearranged as a quadratic polynomial in $q$. You can derive the precise coefficients yourself."
 
@JonasTeuwen Not necessarily so. I believe that JDH mainly makes the point that "hints" often are not very fun to read. It is not like he always gives many details in his answers --- on the contrary, I'd say. But he is extremely good at isolating the main points and techniques involved in a problem and summarizing it, backing it up with good intuition. So I'm sure leaving out some details is perfectly allowed in "JDH-speech".
Of course, a good hint may be worth a thousand words, but often it would be very nice if the answerers elaborated on the idea underlying it: How do you come up with such a hint? What is the basic intuition underlying it?
 
Yes, but I'm not as good at that as JDH :-). I'll keep in mind that I maybe should mention something about how I got the idea. But usually I don't really know that.
 
@JonasTeuwen It may be profitable to invest some thought and work in that... :)
 
Yes it would.
 
Is it just me or does the typesetting of this question look ghastly to you too?
 
10:52 PM
It looks very ugly. Unicode instead of TeX.
Maybe it is just pasted from a pdf...
 
Yes, and the angle brackets are waaaaay too big.
 
Angle brackets? Where?
 
Yes, I was staring at that already for some minutes to figure out where they were...
 
I'll post a screen shot in a few minutes...
Meanwhile I've found the course: see here, page 4
 
Great. How did you find it?
Woohaa! I was correct. Copy-paste!
 
10:58 PM
@JonasTeuwen Oh, I just Googled for "Ax1 ⟨∀∗ (φ → (ψ → φ))⟩; Ax2 ⟨∀∗((φ→(ψ→η))→((φ→ψ)→(φ→η)))⟩; Ax3 ⟨∀∗(((¬φ) → (¬ψ)) → (ψ → φ))⟩; Ax4 ⟨∀∗(∀x.(φ → ψ)) → ((∀x.φ) → (∀x.ψ))⟩;"
It was about the 5th hit.
 
Those angle brackets are much smaller here.
He didn't even take the trouble to rephrase it :-).
 
Probably is a problem with how my fonts are installed.
 
OS X (10.7)?
 
No 10.6, still.
 
The somewhat idiosyncratic notation for MP narrows it down, but I think it's conceivable that the same formalism (and perhaps summary sheet) is also in use elsewhere.
 
11:08 PM
Well done Henning Holmes!
And Sherlock B.
 
I'm Dr. Batson.
 
Great work, you two! =)
 
There's a couple of my recent comments with reference to the assignment that could use an upvote to be visible in the questions.
 
Tomorrow I will talk about the Ornstein-Uhlenbeck operator.
Hmm. Does the bold etc not work anymore?
 
@JonasTeuwen That raises a good point. How do we italicise a part of a word?
 
11:16 PM
By golly, I don't know.
 
Just peeking while waiting for an accident to clear :-)
 
@robjohn Still supervising this exam?
 
@JonasTeuwen I figured you wouldn't know (considering your animation of Uhlenbeck's name). =) I'm more hoping that J.M. or tb will look at my comment and give us the answer!
 
Maybe I should insert an empty URL.
t<a href=""></a>**es**<a href=""></a>t.
That fails miserably.
 
11:19 PM
Test
 
t<a href="math.stackexchange.com">**es**</a>t
Markdown cannot be trolled.
 
Copying tb's comment: Test
Atleast that works
By the way, I upvoted your comment in that question, Henning.
 
It needs moar upvotes.
 
Do the honours then, Jonas.
 
I was the first one.
 
11:24 PM
So, would it be appropriate to email the lecturers of the course with a heads-up?
 
@JonasTeuwen Oh, we were upvoting different comments :)
 
Has such a thing happened before? Start a meta thread first?
 
@Srivatsan Not quite a precedent but related
 
How can you be good enough to go to that university, yet be stupid enough to copy and paste the homework questions verbatim on the internet?
2
 
11:30 PM
@tb Is the triangle x incident a precedent?
@JonasTeuwen Looks like a whole host of students are doing that.
May be they think that the course is too heavy or difficult or something.
 
Yes...
Yes, I can understand that part. But copy the questions verbatim?
 
Oh yes, the questions are all terrible in quality, no doubt.
 
@Srivatsan Don't know. It's rather a precedent for something that got way out of hand.
 
Verbatim copied from the homework (in many cases, homework is just scanned and posted), not typeset (this is not necessary, but still), no motivation, did not acknowledge it as homework.
Do not respond to comments.
 
In any case the policies of the course seem rather strict to me, but maybe this is just some general legal mumbo jumbo universities are to mention somewhere nowadays.
 
11:40 PM
Is there an easier way to prove that lattices in C are discrete than orthoganalizing the vectors?
 
What is a lattice, according to your definition?
 
Specifically, I am asking about problem D on page 12 here: books.google.com/…
 
@tb, @Henning So what now? I am starting to write a meta post. Should I carry on? If we decide to do nothing or do something else (or if you are planning to post it on meta), I will be glad to drop it.
 
Rob
hi
 
I'm not quite sure it deserves a meta post. My thought was just to shoot a quick email to the two co-lecturers and leave it at that.
 
11:45 PM
Yes, it might be good that they know about this. You're not betraying anybody since their name is not known anyway.
 
Ok.
 
@HenningMakholm That would be great, thanks! I see nothing wrong with mentioning it to them and they can decide what they want to do about it. No meta post required, I believe.
 
Okay. Will do.
 
@HenningMakholm Great book, no? ;D
 
@t.b. Also I would like to note, in light of this discussion, that my question is for self study and is not homework.
 
11:48 PM
@JM Sometimes one doesn't know whether to laugh or cry...
 
I love cranks.
 
@HenningMakholm Then the "Megalomania" chapter will give you mixed emotions...
 
Rob
I'm sorry to intererupt your scholarly disscusson but has anyone seen my updated post in "Division by 0" ?
 
@Potato Don't worry :) So you have R-linearly independent points omega_1 and omega_2 in C. Their real and imaginary parts give you a matrix of GL(2,R) (because of linear independence) which gives you a self-homeomorphism of R^2 and the lattice is the image of Z^2 under that homeomorphism. What do you mean by "easier"?
 
Ah ok. Well then.
Very nice.
Is there a way to make a contradiction argument work?
By assuming 0 is a limit point?
 
11:52 PM
Part of the story untold in the book was that Dudley was subsequently sued for libel by one of the cranks portrayed (even though said crank was only referred to by initials). The case reached the federal appeals level and produced a nice opinion by the always readable Judge Posner.
 
"even though said crank was only referred to by initials" - on the other hand, some of the afternotes made the task of figuring the identity of the subject(s) a matter of deduction...
 
Rob
I'm sorry to intererupt your scholarly disscusson but has anyone seen my updated post in "Division by 0" ?
I added extra clarification & a link at the bottom to a through disscussion
 
t.b. I got in a rut trying to prove that having 0 as a limit point of the lattice implied a contradiction. I'm not sure if there's a way to push this through to get a proof though - do you think there is?
that should be @t.b. for the above
 
@Potato I don't see anything easier than re-framing the argument I gave above into a proof by contradiction, which I don't see as a good way of going about it.
 

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