Mathematics - 2014-03-12 (page 1 of 3)

1:27 AM

quite delayed, @Pedro

@TedShifrin Well, kinda.

Are you there?

Nope.

Oh, drats.

I wanted to talk to you.

Anything significant?

@TedShifrin I was interested in crossing agendas for July.

1:29 AM

Ah ... Well, I still don't know my schedule. My CA friends aren't being very cooperative.

Oh.

I was thinking about 3 days of visit.

Well, if it's earlier in July, I'll be here.

@TedShifrin July 28th and twenty days from there.

I'm confused. From meaning following or from meaning before?

28th onwards!

1:31 AM

Oh, so August.

@Anthony Finite subsets are trivial compact pal!

@TedShifrin Aha.

That's what we had discussed earlier, then, @Pedro.

@TedShifrin I forgot. =O

I am absent minded.

Sometimes.

I'm supposed to be old and forgetful.

I can help!

1:34 AM

How so?

By also being forgetful?

LOL, oh. Not sure that helps.

@TedShifrin I had sort of a question.

But you've forgotten?

No! =D

1:36 AM

So?

There is this theorem that says that if a function $f:M\to X$ with $M$ a metric space is continuous over every compact subset of $M$; then the function is continuous over all $M$.

That's very weird. Continuity is a local notion. Who cares about compactness?

Well, if $x$ isolated, we're done. If $x_n\to x$ then $\{x_n\}\cup\{x\}$ is compact.

But I am not sure why this theorem appears in some textbooks.

So then you have the sequential characterization of continuity.

Aha.

1:38 AM

What usually shows up (particularly in complex analysis and PDEs) is uniform convergence on compact subsets.

But I am not sure why this theorem appears as an exercise in textbooks.

@TedShifrin Oh?

Yeah, me either. Maybe just as an exercise for the sake of being an exercise. It's really about continuity on basis elements.

Mhm.

For example, uniform limits of holomorphic functions are holomorphic, but one only gets uniform convergence, typically, on compact subsets.

@TedShifrin My prof. in this summer course told me something of the sorts, yes. That one sometimes proves a function is analytic say by showing they are on every compact nbhd of a point.

1:41 AM

Well, then again, I don't know why one does compactness rather than (open) neighborhood.

Maybe he had a particular context in mind.

*she

oops, my apologies.

"Male until proven otherwise"?

=O

Nah. Almost all my best students in diff geo this term are women. The superstar is most definitely (she's in her third class with me).

Victor

Hi, any person could answer my question? math.stackexchange.com/questions/708852/…

1:44 AM

I don't understand the question, @Victor.

It's not very clearly stated.

2:58 AM

Nice example where it helps to recognize $(1,10,5)$ as hops of $(1,5,10,10,5,1)$

Alexander Gruber

what does the notation $I^\text{ec}$ mean, where $I$ is an ideal?

@AlexanderGruber No idea. Context? Where found? Commutative?

Alexander Gruber

@ccorn here

@AlexanderGruber I didn't do that exercise on nilpotency. =/

I asked a question which I could have answered myself too.

=D

3:15 AM

math

@Utkarsh Is there any good source where I can learn how to use Ubuntu/Linux?

I want to install it instead of Windows.

I'm sick of Windows crashing.

@PedroTamaroff ubuntu.com/tour/en

@Utkarsh Ah, that's cool.

It's virtual ubuntu. but, if you have to do your office work on MSOffice which can't be done on LibreOffice then, you don't need it

And I can download it right? Is there any software I cannot use in Ubuntu that I can use in Windows?

For example, TeXWorks, VLCPlayer, DJVUViewer, Chrome.

3:24 AM

@PedroTamaroff How deep do you want to go?

@Seth What do you mean?

I just want to know how to use it, personalize it, &c.

@PedroTamaroff You should assume nothing works until you know it works.

Hehe. Well.

The point is I think Linux has things installed by typing in programming like code.

@PedroTamaroff Traditionally, universities have scripts or courses covering the user-side aspects of Unix systems. These show the spirit. The administration-side is more specific to the Linux/BSD flavor you are on. I recommend getting familiar with the shell and with the distro's package manager commands.

I cannot do that.

3:25 AM

@PedroTamaroff Well.. I suppose you don't want to learn about compiling kernels and learn shell ;)

@Seth I don't know what that means, really.

@PedroTamaroff You can do it that way, yes.

I want to make my own kernel. Could I?

@Utkarsh You can actually fork it on Git.

@PedroTamaroff Let me pull up a few sources.

okay

3:26 AM

(for learning)

@Seth I'm curious about how you saw my question here.

=D

Here are some: leanpub.com/littleorangeubuntubook ubuntuunleashed.com An Ask Ubuntu mod wrote the first (not entirely sure when it was last updated, but it'll get you started) the second is a big book, you can just read as much as you want.

@PedroTamaroff Just happened to pop in and see it.

This blog/website is also really awesome.

@Seth Cool.

I am downloading Ubuntu now.

Then there's always:

Ask Ubuntu General Room

Normally: General discussion around Ask Ubuntu, Ubuntu & offic...

2

@PedroTamaroff When I made my first experiments, I installed tons of packages (as offered). Nowadays I'd say: Better remain minimal. Install only what you know; if anything is required above that, the package manager will pull it in anyway. You can always install more later, as you needed. Takes only some clicks.

3:32 AM

@Seth ;)

@PedroTamaroff which version?

My main problem is I have what I like to believe is a good laptop, but Windows fucks it up.

@PedroTamaroff I think TeXWorks is available, VLC is, Chrome works, never heard of DJVUViewer

@Utkarsh 13.10.

Windows is not THAT bad

3:33 AM

@PedroTamaroff What kind of specs does it have?

okay

@Utkarsh It is crashing almost everyday with a bluescreen.

@Seth It's an ASUS N53S.

@PedroTamaroff which windows? 7?

@Utkarsh Yes.

hmmm you have installed the antivirus?

3:34 AM

@Seth Here

Mine has a 2GB video card though.

Wow, fancy :)

And 8GB RAM.

Wait.

That last link is bad.

@Seth Yeah, it's a big chunky thingy.

Ubuntu should run fine, although you may have to install a graphics driver (not hard usually)

@Utkarsh Hehe, of course.

@PedroTamaroff I have a similar one.. VERY big and chunky.

3:36 AM

@Utkarsh I am not that oblivious!

However, there could be a lot of reasons Windows bluescreens, including bad hard drive, which Ubuntu won't fix

@Seth Yeah. But it takes a beating. Which is cool.

lol

@Seth Do you have any experience in "cleaning up"?

3:36 AM

@PedroTamaroff As in?

Totally Junk ^

@Seth Not killing people.

@PedroTamaroff I don't understand.. Cleaning what up?

I mean cleaning the HD, the registry, any malicious software, &c.

ah.

3:37 AM

by using CCleaner?

yep, I have experience with that stuff.

@PedroTamaroff You have run SMART check?

@Utkarsh Dunno what that is.

maybe your HDD has failed

@Seth If you work on it, I don't mean to make you work for free or anything, though.

3:39 AM

Do you remember, what message it said at Blue Screen. So, that the real problem could be Identified

@Utkarsh Oh, not really. I don't usually read those. =)

But I had some "file dump" progress and then I just turned the PC off manually.

you know, why i leaved ubuntu?, askubuntu.com/questions/400342/…

@Utkarsh Damn, you done goofed.

hmmm

@PedroTamaroff I bet it isn't very broken. The thing is though, make sure you understand what you're doing before you install Ubuntu, lots of people don't really know what they're doing, and when they want to reverse it, get all muddled up. (I don't know your technical level so)

3:44 AM

@Seth Right.

I don't happen to know any programming language.

I really don't know what is needed.

@PedroTamaroff That isn't a problem ;)

I know HTML :P

@Seth Do you know TuneUp?

@PedroTamaroff Get a Mac. It works, and if you wanna try BSD-style commands in a Terminal window, there is still Terminal.app which does that. VLC, DJview, TeXShop are available too.

3:46 AM

@ccorn Hehe. Macs are ridiculously expensive here.

@PedroTamaroff Tune up utilities?

@PedroTamaroff Not sure I've heard of it.

@Utkarsh Yeah.

@ccorn Like car-expensive.

ah

@PedroTamaroff Looks cool. I'd never heard of that one before.

@Seth lol

3:49 AM

@PedroTamaroff The alternative is to install one of those 1000s of distros, better the ones that do not overload you with stuff you don't need and don't know.

I'll say goodbye now and check my PC for errors. =D

@ccorn What is that?

That website is scary.

Too many hyperlinks.

Yeah, Ubuntu is not the only one

Meh! When I was 9, I used that website

to see what distros are the best

Well I'm going to go to bed soon. If you have any questions @PedroTamaroff go ahead and ask them in the Ask Ubuntu general room. You might also be able to get Windows help on Super User.

@Seth Good Night!

lol

for me, its Good Morning

:P

r9m

3:58 AM

@Utkarsh hello :)
do you know how to get full screen resolution in wine (ubuntu 12.04)?, while I play windows games (AOE2) on ubuntu ... I get a diminished screen resolution .. how can I make it full resolution ?

@r9m Have you tried to set the fullscreen mode from the game? (It works like that, example with WoW)

r9m

@Utkarsh ya I tried that ... but it isnt working

red this then askubuntu.com/questions/270730/…

therefore you may want to consider to install gnome-session-fallback Install gnome-session-fallback and start a fallback GNOME session at login in case we plan to run a Wine fullscreen application.

r9m

@Utkarsh oh ... okay :) thanks a ton :)