« first day (761 days earlier)      last day (780 days later) » 
00:00 - 20:0020:00 - 00:00

hhh
8:00 PM
@JayeshBadwaik Can you recommend me book or exercises?
 
@hhh *me
 
hhh
@PeterTamaroff sure, fixed :)
 
@hhh I am looking at your book right now. Considering it is based on halliday resnick, I think its exercises are good enough. Will just see and let you know though.
 
In case you want another book you can choose any one of electrodynamics griffith, electromagnetics nathan ida, field and wave electromagnetics david cheng. titles are not exactly these but I guess the books are popular enough to show up on google.
 
8:05 PM
You burned me and left me badly disfigured! laughed the Indian boy.
 
Have you guys heard about John Rainwater?
Got the idea by looking at JT and anonymous.
 
@JonasTeuwen wonderful!
 
@JonasTeuwen That was like Lewis Caroll giving the Queen the next book he published after "Alice in Wonderland" :P
 
You and your books...
 
8:10 PM
Hahaha. Okay I will shut up. More integrals, less books!
 
@JayeshBadwaik less integrals - more zeta functions ...
 
@Jonas I'm looking at the Dleft troll work. I don't get what you mean when you write that $[0,1]^[0,1]$ endowed with the product topology "is the space of all continuous mappings on [0, 1]." The space contains all mappings $f:[0,1]\to [0,1]$, not just continuous ones.
 
Oh, I thought that made them all continuous.
I thought it was the same as the weak topology here.
 
Right now I am on this problem. Show that
\begin{equation}
\int\limits_{0}^{\infty} x^{-x} \mathrm{d}x = \sum\limits_{n=1}^{\infty} n^{-n}
\end{equation}

I can do such things by writing this out as a riemann sum and then evaluating. However, is there some other method which we can apply here? Any other methods of converting integrals to sums?
 
hhh
@JayeshBadwaik Thank you will check them.
 
8:25 PM
How can I make W|A plot some 3D points?
 
Slice it.
And then combine!
 
@JonasTeuwen Dude.
 
8:42 PM
@MichaelGreinecker I wanted to take a space with large cardinality as per your suggestion.
 
Is there anyone here who can help me with some vector algebra?
 
@PeterTamaroff I am sure there are - I might even remember a bit myself
 
Slice and combine ;-D
 
@JohnJunior Do not take offense man. It is a line from a song by beatles.
 
@JohnSenior OK.
The task is as follows.
We're working on $\mathbb R^3$
 
8:53 PM
@PeterTamaroff I'm happy so far ...
 
We got $\Pi:2x-y+2z=4$, $P=(2,2,2)$ and $Q=(1,0,1)$
 
@PeterTamaroff OK
 
We need to find a plane $\Pi'$ such that $Q,P\in \Pi'$ and $\Pi'$ contains another point $R$ from $\Pi$ such that $d(P,R)=d(P,\Pi)$.
I have done some work already.
Namely, we have that $d(P,\Pi)=2/3$
Also, say $R=(x_0,y_0,z_0)$
Then we need $(x_0-2)^2+(y_0-2)^2+(z_0-2)^2=4/9$
Now I will plug in $\Pi$ to get things going =P
 
Wouldn't $R$ be the point where the perpendicular from P intersects the $\Pi$ plane?
 
@JayeshBadwaik pretty sure that will be true
 
8:58 PM
@JayeshBadwaik I need that $2x_0-y_0+2z_0=4$, too.
 
Then you already have $R$, since $d(P,R)=d(P,\Pi)$. You just have to take the line passing through $P$ and with the direction $(2,-1,2)$ and then find out the point at that distance. So now your 3-variable problem is now one variable (parameter of the line).
 
@JayeshBadwaik Let me think.
 
@JayeshBadwaik yep
 
@JayeshBadwaik $(2,-1,2)$ is the normal vector.
 
@PeterTamaroff yup
 
9:03 PM
@JayeshBadwaik I'm trying to find a plane that contains two points from another plane $Q$ and $R$, and another $P$-
And with some distance contraints.
@JayeshBadwaik It is true that $d(P,\Pi)=2/3$ right?
 
If you can find the three points. Then the normal vector of the other plane will simply be $\bar{PQ} \times \bar{PR}$
 
@JayeshBadwaik Yes, I use that often
@JayeshBadwaik Since $Q\in \Pi$ I can calculate the distance as $|(Q-P)\cdot N|/||N||$, yes?
 
@JohnSenior Serious issue here.
No beer!
@JayeshBadwaik What is wrong with you? 8-). Just pick Jackson, start working (with mouth shut).
 
@JayeshBadwaik I have done that integral by writing $x=e^{-u}$ and then writing $x^{-x}=\sum\limits_{k=0}^\infty\frac{e^{-ku}u^k}{k!}$
 
9:07 PM
@JonasTeuwen Sh*t!!! - is there an emergency helpline you can ring?
 
Rob, the master of Syntax.
@JohnSenior I think they will blacklist my number.
You mean like 0900 - BEER-NOW ?
 
@JayeshBadwaik OK, so now how do I work out what $R$ must be?
$R$ is on a circle around $P$
 
@robjohn Oh boy. That is nice :-)
 
@JonasTeuwen yep - we have something similar here in Warrington UK
 
@JohnSenior Do they have more beer than just one kind...?
 
9:09 PM
@JayeshBadwaik Then you finish off using the $\Gamma$ function to integrate each term.
 
If I have a beard I will be John Junior. My father is John Senior.
 
@robjohn Yup. :-)
@PeterTamaroff Why is it a circle? P is not in $\Pi$ and the distance to the plane is the shortest distance, surely it must be attained at a single point?
 
I would be glad to have you as my brother :)
 
@JayeshBadwaik I mean, I have just fixed one part of $R$
 
since $R$ is in the plane.
 
9:10 PM
@JonasTeuwen here
 
the one that asks for $d(P,R)=2/3$
Now I need to finish.
 
@JohnSenior Pretty cool.
 
@PeterTamaroff The sphere of the radius 2/3 around P intersects the plane $\Pi$ at only one point (touches rather)
 
@JonasTeuwen The bird is greater than or equal to the word.
2
 
@JonasTeuwen I think I found out what is wrong with my Linux desktop
 
9:13 PM
@JayeshBadwaik But I'm being ask that $P\in \Pi'$.
 
@JohnSenior It does not run my LFS?
 
@JayeshBadwaik Let me rewrite the problem.,
 
@PeterTamaroff yup, that would be good.
 
@JonasTeuwen I have the OS installed on an SSD, and it seems to have developed errors - I have files that I can't delete :(
 
@JayeshBadwaik Given $\Pi :2x-y+2z=4$ and $P=(2,2,2)$, $Q=(1,0,1)$, determine a plane $\Pi'$ that contains $P$, $Q$ and a point $R$ of $\Pi$ such that $d(P,R)=d(P,\Pi)$
 
9:14 PM
@JohnSenior Somehow a bottle of wine sounds so much more refined than a crate of beer. :-)
 
@robjohn I agree - but the area of North West UK where I live is not well-known for being refined :)))
many of the guys round here can tie their shoelaces without bending down ...
 
@JayeshBadwaik I could visualize it.
 
@PeterTamaroff Yup. So you have a point $P$ outside a plane $\Pi$. Now you have the shortest distance from $P$ to $\Pi$ (which will be the perpendicular distance). Now, another point on $\Pi$ namely $R$ is at the same distance from $P$. surely $R$ must be the point where the perpendicular from $P$ intersects the plane? Followed till here?
 
@JayeshBadwaik OK, yes.
 
9:20 PM
So, now your $R$ lies on a line Which can be given as $\bar{X} = \bar{P} + t\bar{N}$, agreed? Where $N$ is the normal vector of the plane.
$t \in R$
 
@JayeshBadwaik OK, so I need to find that new $N$, right?
 
@JayeshBadwaik But that also depends on $R$!
 
You need to find the appropriate $t$.
 
@JayeshBadwaik So that $||t N||=2/3$?
 
9:21 PM
Yup
 
@JohnSenior Oh, reinstall OS.
@JohnSenior Does the linux kernel fully support your SSD?
The probability brother is here!
Too little Gaussians in my work.
Or too much.
I am trying to figure out what the interesting class of differential operators is where their invariant measure is some nice probability measure such that the eigenfunctions are of (pseudo)binomial type.
 
@JayeshBadwaik But what is $N$ then???
If I haven't found $\Pi '$ yet.
 
@PeterTamaroff Normal vector of the plane $(2,-1,2)$
N is the normal vector of $\Pi$
 
But maybe Ornstein-Uhlenbeck and Gaussian is enough when I have these cool SDE transformation thingies.
 
@JonasTeuwen I was planning to reinstall this evening, but it is a bit late now
 
9:25 PM
Puuurfect.
Only takes like half an hour or so?
 
@JonasTeuwen I thought it did - but I think I will reinstall on a standard drive (I have lots of them lying around)
 
@JohnSenior Yeah, no need SSD.
 
@JohnSenior Good. I think even now SSD's are to be preferred for only read-only operations. Even now they have only like 1 million write cycles limit.
 
But I need a version of Linux which doesn't take all my time to keep it updated - but is also stable (unlike Ubuntu / Mint / etc)
 
My whole system fits in the memory.
 
9:26 PM
@JayeshBadwaik I can't get it.
 
@JayeshBadwaik Per cell. Do you know how bloody many cells there are? RANDOMIZE.
@JohnSenior No Bullshit Linux. Made by me.
Also, Arch.
The good thing about mine is that I remove all the Linux bits.
 
@JonasTeuwen Arch sounds like fun - how complex to install?
 
I like the Plan9 and BSD things better.
 
@JonasTeuwen LOL
 
@JohnSenior If medium-level of knowledge then not so hard.
@JohnSenior There is a very good Wiki.
 
9:27 PM
@JayeshBadwaik OH; SHIT
 
@JonasTeuwen Yeah, but only in recent version do they have proper reuse things where they will not write unless necessary. If your hard drive is around 2 years older, then it doesn't.
@PeterTamaroff Exactly. :-) :D
 
$R$ is just $P$ projected orthogonally onto the plane¿
 
user19161
@JohnSenior Debian, full stop.
 
@JonasTeuwen will give Arch a try tomorrow :)
 
@PeterTamaroff If you want to say that, yes you are correct. :-)
@JohnSenior Arch now uses installscripts to install.
 
user19161
9:29 PM
@johnjunior I see names are getting complicated in here.
 
@JayeshBadwaik Good.
 
@JonasTeuwen They threw away the aif after it was unmaintained for too long.
 
user19161
I think XFCE is very good, but it still uses several GNOME components at least in Xubuntu, so I will stick to GNOME.
 
user19161
Also, Ubuntu GNOME shell spin will be out next month as an official derivative.
 
@JayeshBadwaik S I need to find $\lambda$ such taht $|\lambda|\cdot ||N||=2/3$?
 
user19161
9:32 PM
However it seems that Firefox and LibreOffice won't be installed by default in the spin.
 
@PeterTamaroff Yup.
@WillHunting I haven't opened LibreOffice for almost atleast. six months now
 
user19161
@JayeshBadwaik LibreOffice is the only replacement for Microsoft Office. If it goes down we are all finished.
 
@WillHunting It won't go down. I am saying that I don't actually use it. currently that is. And it is not on the default, you can always install it yourself.
 
user19161
There will be a GNOME OS and even a Firefox OS in a few years.
 
@WillHunting and there is the lightweight JoliOS
 
user19161
9:36 PM
@JohnSenior Do you like it? Never heard of.
 
@WillHunting I've used it - but don't really like it - but it can be useful
probably called Joli cloud now
 
@JonasTeuwen You use a desktop? (as opposed to a laptop)?
 
user19161
It is sad Ubuntu chose Unity over GNOME shell. Otherwise it could be the best OS instead of Debian.
 
@JayeshBadwaik I use desktop, tablet and laptop?
Depends where I am.
 
@JonasTeuwen I meant for your LFS.
 
user19161
9:39 PM
GNOME is radical but organized. Unity seems a disorganized mess to me.
 
@JayeshBadwaik Oh, desktop.
@JayeshBadwaik When you have a laptop you usually want to work on it and don't really want to have that things break when having to give a talk.
 
user19161
@JonasTeuwen You are one of the cool kids.
 
Why.
I don't want to be part of the cool kids. They are often even more retarded than I am.
4
 
user19161
People with tablets are cool kids.
 
gotta go - back later folks
 
user19161
9:40 PM
People with tables are hot kids.
 
@JonasTeuwen Yup. I tried installing LFS on my laptop though and it was giving weird hardware errors, so I am now on tried and tested Arch and don't want to mess with it currently. Scavenging for desktops currently.
@JohnSenior Later.
 
user19161
@JohnSenior Bye.
 
bye folks
 
Hi @Americo.
 
user19161
9:49 PM
@JayeshBadwaik Rather dramatic. But I think GNOME shell is the desktop for the future, together with Windows 8!
 
@WillHunting I like the idea of the search/predict based models for navigation. I dislike the idea of the complexity (ugliness rather) of the underlying SQL/similar software.
 
user19161
@JayeshBadwaik I like one desktop for desktops and phones. GNOME is that desktop, not Unity.
 
@JayeshBadwaik What. I just mean take kernel and download your own tools.
 
@JonasTeuwen NVIDIA Graphics Card. This was around a year and a half ago and nouveau was not good enough. I did not want any direct binary driver, which would break my X at every upgrade.
 
10:00 PM
Oh, I have intel graphics.
 
Also my wifi is broadcomm, not exactly linux friendly.
Well, I will be going now. See you all later.
 
@JayeshBadwaik Dude, apparently the plane uis $\Pi':x=z$
 
hhh
10:17 PM
about a book, 34.13 -equation -- really $\frac{E}{B}=c$ where $c$ is the speed of light or some other constant?

http://200.105.152.242/olimpiada/file.php/1/LIBROS_OLIMPIADAS/FISICA%20SERWAY/34-ElectromagneticWaves.pdf

I found something about antennas :)
(it does not show how to deduce the direction with Maxwell -equations, just state things)
 
hhh
10:45 PM
@JayeshBadwaik Cannot find the books, have to go library :(
 
11:03 PM
Very few people realize the enormous bulk of contemporay mathematics. Probably it would be easier to learn all the languanges of the world than to master all mathematics at present known. The languanges could, I imagine, be learnt at a lifetime; mathematics certainly could not. Nor is the subject static. Every year new discoveries are published. In 1951 merely to print brief summaries of a year's mathematical publications required nearly 900 pages of print. In january alone, the summaries had to deal with 451 new books and articles. The publications here mentioned dealt with new topics; the
4
 
hhh
@GustavoBandeira Thank you for sharing, good quote.
 
@hhh Yep. =)
 
hhh
@JayeshBadwaik I could only find solution manual, veethaadiyani.blog.uns.ac.id/files/2011/01/…
(I think I will give up this search, just contacted my teacher about the direction -- asking for clarification what he meant with the $\hat k$ and $\hat j$. For me, it looked arbitrarily chosen but @JayeshBadwaik apparently claimed that they could be deduced from Maxwell equations)
Sov gott!
Hey!

Now I know it.


Q1. $\bar E = E \cos(a\bar x+ b\bar y)$ is a planar wave in $x-y$ -axis, right?
Q2. $\bar E = E \cos(\bar r \cdot \bar h)$ is a planar wave in the direction of $\bar h$, right?
Q3. $\bar E = E \cos(\bar r \cdot \bar h)+E\sin(a\bar x +b\bar y)$ is some combination of a planar waves, right?
Q4. $U(\bar r, t) = A_0 e^{i \left( \bar k \cdot \bar r - wt + \phi \right)}$ and this is just a combination of planar waves, right? You can break this up to trigonometric functions each of which are planar waves -- so the sum of planar waves is ???, is it a planar wave?
Moved the questions to my chat with unsolved problems here.
...I wish universities used Stackexchange :P
 
11:32 PM
Hey, does anyone here know anything about math research related to natural language, specifically semantics?
 
hhh
Q0904_5: Is the some of planar waves a planar wave?
 
@Rachel Let me check something.
 
hhh
A0904_5: Suppose $\bar A=\cos(\bar x +wt)$ and $\bar B =\sin(\bar y +\bar z +wt)$ where $t$ is time. Now their sum $\bar A + \bar B$ is moving in the 3D -space $xyz$ over time, right?
 
I don't have a specific question about a problem, by the bye. I am trying to find people and places for grad school.
 
hhh
Hey, this is totally trivial issue :D
 
11:36 PM
@Rachel I guess this book may deal with what you're searching for.
 
@GustavoBandeira: yes, it might be interesting. But I am more interested in the structure of natural language, or a structure that can do the same things.
 
@Rachel I guess this is one of the points of the book I mentioned, look here.
 
@Gustavo: Yes, it's interesting. MIT is one place on my list currently.
 
@Rachel Yep. In your case, I guess it's a must
I've found this.
I just don't know if it's going to be useful.
 
I am familiar with the book they mention (Patree et al. 1990). I believe these people are at Stanford.
Not Barbara but the authors of this paper.
Yes, CSLI is Stanford. This book looks like it is a basic intro to some math that is useful in linguistics.
I am mainly looking for people who know about logicians or linguists currently taking students and doing math research in semantics.
I'm having a lot of trouble finding people working in this field.
 
11:52 PM
@Rachel I guess it's relatively rare.
 
Yes, this is why I am looking for people who know about it here.
 
It's one of my interests, but I'm td4i atm.
 
td4i?
 
Too dumb for it.
 
Ah. Maybe you underestimate yourself or overestimate others. :^)
 
11:55 PM
@Rachel No, I believe I can learn - I just don't know much by now.
 
00:00 - 20:0020:00 - 00:00

« first day (761 days earlier)      last day (780 days later) »