Mathematics

@PeterTamaroff By contradiction, if $y > \limsup A$, then $y$ cannot be a limit point! Since, there will exists a $\delta$ such that $S_{\delta}(y)$ will not have any $a \in A$, because if it does, then there are infinitely more $a\in A$ (for every $\delta$) and hence $a> \limsup A$ for infinitely many $\delta$ which is a contradiction.

Jayesh Badwaik

5:31 AM

@BenjaLim Dude, I told you so!!!. (I know its not polite, but had to do it!! :P :P)

23 hours ago, by Jayesh Badwaik

@BenjaLim The guy is going through his first chapter in Artin, and you gave him endomorphisms!

N3buchadnezzar

6:25 AM

Hmmm

Martin Sleziak

I think I remember seeing a post here, where educating PhD student how to teach was discussed. I think I remember that someone mentioned there that in "his young days" they simply told them to teach and they did so. (Without being taught a special course about pedagogy or having to hand out an essay on this.) And many people gave interesting comments related to this type of courses there.

I believe it was here or at MO. (But I can be wrong - it might have been a blog or an article.)

Does anyone remember something like this?

The only related thing I was able to find was this MO thread: Teaching a pedagogy course

N3buchadnezzar

@MartinSleziak Hey

Martin Sleziak

Morning.

OldJohn mentioned that he was watching England match yesterday.

N3buchadnezzar

Cool

I remember seeing that post aswell, but I can not find it either.

Martin Sleziak

Now I see that Argentina defeated Uruguay - that's good news for Mariano and Peter Tamaroff, I guess.

N3buchadnezzar

6:37 AM

The logarithmic identity $\log A + \log B = \log AB$ only holds when $A\wedge B>0$ right?

Martin Sleziak

Well $\log$ (as real function) is only defined for positive arguments, so you need $A>0$ and $B>0$. Otherwise the equality does not make sense.

If you are asking about complex logarithm, I know almost nothing about complex analysis :-(

N3buchadnezzar

Yeah

Just a friend asked me about an integral, and I have some problems justifying the steps to him

$$ \int_{-\sqrt{2}\:\:}^{-1} \frac{2z^2-1}{z}\,\mathrm{d}z $$

Martin Sleziak

Substitution $u=z^2$ should change this to rational function.

I believe.

Or $t=2z^2-1$.

AbstractionOfMe

im so bored

N3buchadnezzar

Yeah, otherwise you have to justify the addition of negative logarithms.

user19161

6:44 AM

@MartinSleziak Probably, though some want their home team to lose.

Martin Sleziak

I don't see anything bad about that. If someone is a fan of team from different country (or no fan at all), I don't see any harm.

Welcome to MSE morning sport's special.

2

AbstractionOfMe

can i think of a naive set as a cloud of objects zooming around

Matt N.

Qiaochu ignores me. Can anyone else help me?

Martin Sleziak

7:36 AM

I have no doubt that some local knot-theorist will have a look at it.

Unfortunately, I am not knot-theorist.

Rajesh D

10:04 AM

Hey @JonasTeuwen

skullpatrol

11:50 AM

5 hours ago, by Matt N.

Qiaochu ignores me. Can anyone else help me?

Nimza

1:20 PM

Hello everybody!

Is there anybody who uses Matlab?

Jayesh Badwaik

1:31 PM

@Nimza I have used it in past, but haven't used for a while. Also, it is a very big resource, so if you want to ask something area specific, I might not be able to help.

Nimza

@JayeshBadwaik I have a problem with gif animations. I post exactly an example from the internet but it doesn't work

Jayesh Badwaik

can you link me to it?

Nimza

1 sec

mathworks.com/matlabcentral/fileexchange/21407-gifaddframe/…

@JayeshBadwaik I post an example that is on right of ">>" symbols

Jayesh Badwaik

Error in ==> gif_add_frame at 53
A = getframe(h);

Are you getting this error?

Nimza

no

I have no error, but output gif file consists of a single frame

Jayesh Badwaik

1:36 PM

Okay.

ohh

just a sec

let me test it myself

Nimza

hm. new frames are really added (size of file changes)

Jayesh Badwaik

I am getting a rotating sphere

colored in light blue and yelllow

Nimza

in gif or only in program?

Jayesh Badwaik

in gif

Nimza

oh...

robjohn

1:45 PM

It's closing time.

Jayesh Badwaik

@Nimza you might want to use imwrite to make a gif from the program.

Nimza

@JayeshBadwaik and even "movie" command doesn't work. I think I have some problems with matlab

Jayesh Badwaik

@Nimza Hmm. Which version do you have? (I am on 7.12.0 R2011a)

Nimza

@JayeshBadwaik 2011b

Jayesh Badwaik

@Nimza So on a more recent version than me. Hmm. Strange.

Nimza

1:49 PM

very strange... I used such functions some years ago

Rajesh D

Hi @robjohn

Nimza

@JayeshBadwaik I'll try to change render

Jayesh Badwaik

@Nimza Hmm. Yup, probably that might help.

Nimza

@JayeshBadwaik epic win!

Jayesh Badwaik

@Nimza render problem?

Nimza

1:59 PM

@JayeshBadwaik yes, I've changed OpenGL to painters

Jayesh Badwaik

@Nimza Ohh. Good! Gosh, how subtle can a problem be! I would haven't got that by myself.

Jayesh Badwaik

2:46 PM

Busted

robjohn

3:13 PM

@RajeshD Hi there. Sorry, I had to leave. I'm back for a bit.

Rajesh D

@robjohn Weekend blues?

robjohn

@RajeshD No, this week has been bad. One of our friends is in the hospital with complications due to cancer. My wife has been to the hospital for about 10 hours a day and I have been at our friend's house for 10 hours a day feeding and watching her dogs. That leaves us a few hours (after I walk our dog) to see each other.

Rajesh D

@robjohn sorry to see such a thing. Hope things get better for your friend.

Transcript for

$Mathematics$ Mathematics