12:14 AM
12:25 AM
If I NEED to prove something for one case (e.g. $a = 1$), but then I actually go on prove it $\forall a \in \mathbb{R}$, how do I introduce this? Is "For maximum generality, take $a \in \mathbb{R}$ good?
You cannot alter the theorem statement?
That's what I thought. I'm a newb at doing this, thanks.
12:59 AM
Hello!!!Good night!
@PeterTamaroff,@GustavoBandeira!
Oi, mary.
@GustavoBandeira E aí?
e o troço que você ia mostrsr?
Tô aqui com ela. :-)
do it.
Vai ficar mais tempo? É que estou na rua.
1:12 AM
ok.
E aí? Tá bem?
@GustavoBandeira yep.and u?
Também. Ce conhece o livro polynomials do Barbeau?
não...why?
Tô lendo ele.
1:16 AM
is it good?
É bacana. :-)
tô olhando ele aqui...
@BenjaLim Hey, Ben! Have you changed your Skype user?
I have you on my skype...
É leve, mas eu não sei quase , então serve.
@GustavoBandeira tá em que parte?
1:23 AM
Bem no começo. :-(
Learning the nuts and bolts of programming. Python is awesome.
@KannappanSampath Python is.
@GustavoBandeira how was your trip yesterday?
Cool.
@GustavoBandeira Good.:)
Bbl
Almost at home.
1:39 AM
ok
Its impossible to type latex in the cell phone.
what do you wanna write?
@MeAndMath $\sup$?
@PeterTamaroff what?
Sup _ whats up
I guess
1:44 AM
Is that it,@PeterTamaroff?
@MeAndMath Is that you?
@PeterTamaroff Yes.Itsa me!
@MeAndMath Oh, good. For a moment I doubted.
@PeterTamaroff Why??
@MeAndMath I have my reasons.
1:47 AM
@PeterTamaroff o.O
He's trolling...
@MeAndMath =D
@PeterTamaroff Pedro,Pedro...
Silly marymath......
@GustavoBandeira I'm not silly...
1:51 AM
Yes, you are. :-)
@GustavoBandeira y?
Well, I start to feel that Pedro, Gustavo, MeAndMath all know each other IRL.
@KannappanSampath no.I'd like to,but no.
Look, Me and Peter were neighbours once.
We lived in the glorious nation of the Trollland.
But war forced us to flee to other places in the world.
Pronto, Mary.
I took refuge in Trolland.
1:54 AM
É assim.
@GustavoBandeira já chegou em casa?
Sim.
@GustavoBandeira assim o quê?
First world problems: I finished all the mission on Modern Combat 3. What do I do with my life now? I know: BEER!
As pessoas têm um negócio com cerveja...
1:56 AM
@MeAndMath PORTUGULUBRESE!
MWAHAHAHAH
Deixa eu pegar o negócio no meu deskto
user19161
@PeterTamaroff Have tea or coffee instead Pedro!
@WillHunting I'll have coffee! With an alfajor!
1:58 AM
@WillHunting yES!
user19161
@meandmath What does your avatar show?
@WillHunting Chaplin.
@WillHunting cHARLIE CHAPLIN
@WillHunting Ignorance is not bliss in this case.
Charlie Chaplin is bliss.
user19161
@PeterTamaroff Only Pedro is bliss.
user19161
1:59 AM
@MeAndMath Interesting how you spell his name.
@WillHunting why?
user19161
@MeAndMath aPPLE bANANA cHERRY
@WillHunting In that order? I think not.
@WillHunting that was an accident...with caps
user19161
@MeAndMath Yes, I like to make stupid jokes.
2:01 AM
1 - I said it was bullshit. =D
Now let me try to remeber what was it.
user19161
@GustavoBandeira That is bullshit.
@WillHunting No, this is dog.
X,Y,Z worked as placeholders, A,B,C is relative to their positions and the s's are their size, I guess.
I wanted to plot various values for it and see what image they would generate. =D
user19161
@EdGorcenski No, when one encounters problems everywhere, look to the consistent factor the world, not themselves.
@GustavoBandeira Do you realize how sad that is?
user19161
2:04 AM
I just invalidated another chat flag.
user19161
I call these people the flaggers.
user19161
I flag things on main to keep the site distraction free, but I think chat is free for all.
user19161
If there is a problem I think it should be ironed out with the individual personally to better the world.
I usually spend sometime ploting functions, it's cool.
For anyone who feels like wasting 1-2 minutes: i.imgur.com/2sMQL.png
user19161
2:06 AM
Removing specific messages does not better the world, just leads to more hatred and evil.
@MeAndMath Tá guardando o insulto, né?
@GustavoBandeira qual deles?
user19161
I think this world cares too much about superficial things and not things which truly matter, and the above is an example.
@WillHunting You should call them: "the battlecruisers"
@MeAndMath Porra, tem vários? =(
@wj32 Hint: The relation is equivalent to saying the image of L(u,v) under the quotient map contains 0; and the quotient space is 1-dimensional.
2:08 AM
My mom brought me some coffee.
user19161
@GustavoBandeira By the way, mom is AmE and mum is BrE.
user19161
Sometimes I feel the Americans change the spelling just to be different.
wow
the beatles
STAR TREK!
2:10 AM
Did you have Set theory at university?
user19161
What is Gus and Me talking about now?
Not yet
user19161
@GustavoBandeira Set theory can be done at many levels. Elementary set theory is covered in schools for example.
user19161
Just know venn diagrams, union, intersection, complement, notation etc.
Will/Jasper, your real name is not Jasper, right?
2:13 AM
i'm teaching myself
user19161
@GustavoBandeira It is. But I am not sure who the real me is yet.
@anon thanks
As you're from singapore, your name should be something like Yu-Li Kung-Fu Shan.
user19161
@GustavoBandeira No, you don't know about names here!
What's the most common name there?
One of the most common names here is Gustavo. =/
user19161
2:14 AM
There are various patterns, I shan't elaborate.
@GustavoBandeira no,it's not...
user19161
@gustavo If you want to cover formal logic and set theory though, I recommend Goldrei's Propositional and Predicate Calculus followed by his Classic Set Theory.
What is then?
At an extreme level of locality, my name is the most common name here.
@WillHunting I guess I'm gonna love set theory.
2:16 AM
josé,joão,lucas,luís...
user19161
@GustavoBandeira I think you worry too much about metamathematics. Just start studying the mathematics itself already! But really, now you are at the precalculus stage. Just get all your elementary algebra, geometry, trigonometry, sets, combinatorics right first.
@peoplepower Imagine if I were living in the moon: "The most common name here is Gustavo" would be plausible, In this case, I would be alone at the moon. The mode of every set with only 1 element called n is n!!1
@WillHunting I'm doing it, but I'm so fucking curious!
user19161
@GustavoBandeira Yes, the danger is to ponder too much on these matters without really studying them.
user19161
But to ponder a little is good.
Will, what is predicate calculus?
It's something that let me curious, but i have no clue of what it is.
2:20 AM
I really love to stay here and to you, guys , but I gotta sleep! good night!
@MeAndMath Banana de pijama!
boa noite!
user19161
Boa noite.
2:23 AM
Boa noite.
@WillHunting I've read this but couldn't understand much.
@MeAndMath You're weak.
2:59 AM
@KannappanSampath Yes I have changed it.
3:21 AM
0

As technology evolved, some ideas and methods became obsolete. What mathematical ideas entered this state due to technology progress? We could consider that doing some mathematical operations done by hand are obsolete because we can do them on computer, for example. But these operations still ex...

Is this question too dumb?
Maybe I'm asking too much. Dunno.
3:39 AM
@GustavoBandeira Do questions have IQs?
@robjohn Well, I fell ashamed of asking something that is not glorious.
And also "donwvote-o-fobia"
I usualy think I'm elaborating crap questions and all that. Argh.
4:09 AM
...
Are there "trolling mathematicians"?
In the history of mathematics, who was the greatest trolling mathematician?
@GustavoBandeira You bet!
By now, I'm aware that @PeterTamaroff is going to add something on this field...
I almost asked it on MSE, for serious.
Its time he changed his name to Trollaroff for better recognition.
I'm aware that Archimedes sent fake proofs to his friends, for knowing which of them were stealing his work.
@GustavoBandeira If you start asking stuff like that, we might just have a gustrollo Bandeira :P
4:16 AM
I guess it was Archimedes.
@GustavoBandeira Well, it was incredibly difficult to convince Fermat to show his proofs. If we did not know any better.....
@JayeshBadwaik Why he didn't want to show it?
Every mathematical field started with one simple question, here goes mine:
-Can we make a mathematical body of knowledge about trolling?!
@GustavoBandeira Its already a work in progress. But then the definition of troll is much much wider.
12/9/2067.

Today, Gustavo Bandeira earned his Fields medal in recognition for his work on Topological Trolling Theory.
The current economically relevant are of course the patent trolls. I guess, you would find a lot and lot of studies on it.
4:26 AM
@GustavoBandeira Trolls can be of various types. Mostly, resources would be invested to study the behavior of trolls which are currently economically relevant.
Yep. But I guess this wouldn't be math specifically, wouldn't it?
@GustavoBandeira No, I guess. Mainly statistics (applied)
But thing is definition of troll is dependent on definition of mathematical ideas.
I guess it would be more something related to behavior. This would be the end and statistics would be the means.
You cannot have a troll independent of the mathematics you do. Hence, all that troll does is emphasize some particular aspect of results while deemphasizing others, and in a way try to present a distorted picture.
How well the picture is distorted is a matter of statistics I would say.
4:32 AM
Yep.
Jay, you know about programming, don't you?
Yup. But not user interface kind. Mainly algorithmic.
I've learned to program kinda instinctively on Mathematica, BUT I guess I'm still in a very basic level. I learned this way because of two aspects (I guess):
1- Mathematica is REPL, It allow me faster experimentation and results.
2- Mathematica have a nice reference, where you can search for a function that do something and in the help page of this function, you can read suggestions on similar functions.
As you can see in this example.
I've searched for a function and in the see also part of the page, there are other similar functions enlisted.
Missed Ben.
@BenjaLim Hey, OK. I wrote you a mail sometime ago about coffee. So, reply to that with your skype name. K?
@JayeshBadwaik Where can I find such comprehensive references on other languanges?
Talking about REPL, there's one cool site: Ideone
@GustavoBandeira Hmm, depends on the language (of course). Python is really well documented.
Their documentation is on their website.
For c++ , I guess Stroustrup's books are the primary reference along with a text book like C++ Primer or Modern C++.
Once you are upto that level or even before that, hangout at stackoverflow.
Cppreference.com cplusplus.com are good also.
4:44 AM
While I was 16 years old, I tried to program with Delphi, I always had to make an annoying procedure to see it running:
-Write the code.
-Compile.
-Run.
-Get naked.
-Now the program will run! Voilá!
Delphi? never used that.
It seems that Delphi is Object Pascal.
At the time I didn't know
I learned on BASIC when I was 8 I guess. Then I graduated to C when I was 11. ASM and C++ at 14. Python/Haskell at 17. A little bit of LISP a year later. I had too much free time to worry about programs not running then!
Anyway, there are three aspects of programming I believe.
1. Algorithms
2. Data Structure Representation in Memory
3. The actual Syntax
@JayeshBadwaik How did you learned basic while you were 8? Your parents provided you some guidance?
@GustavoBandeira I had a toy computer which had basic and there was a manual with it. I would play around with stuff in the manual.
Print "hi there"
10 Print 10
and stuff like that.
I did not know that I knew basic later till when I was 12 when it was taught in our school and I was like, oh I already know all this stuff. :P
4:51 AM
While I was 7, I said: "Dad, I want an electronics course". He didn't gave me it. =(
I always thought it was some game designed by the toy computer people.
My mom gave me it when I was 16...
Do you use LISP now?
@GustavoBandeira hmm. I did not particularly like the transistor operations when I was in high school. I thought they were too messy. And then I spent my senior year working on how to improve transistors (and that project was by choice :P )
I have interest on it, I'm VERY curious on the metaprogramming stuff.
Naah, as I said, I learnt a very little of lisp. I can write small one off programs here and there. Nothing more.
@GustavoBandeira To tell the truth, there is not much magic in it. Even I was initially attracted towards LISP by the same reason, but it is basically higher order functions I would say.
I do not mean to say, it is not interesting, but that since then, other languages have evolved to do what LISP used to do and what made it so popular.
4:56 AM
I have a love for AI, then I've read somewhere that some aspects of AI are made with the metaprogramming feature.
@JayeshBadwaik What languanges? I guess I know only Haskell that has some similarity with LISP.
@GustavoBandeira LISP is the only language I know which is completely reflecting (that is, it is its own meta language)
But basically ASM is a metalanguage too.
and so if you use pointers in C properly, you can get a meta language with C also.
But basically ASM is a metalanguage too.
it is like, you can write object oriented code in fortran, but is it worth it?
Is it?
And in that respect, in recent times, languages like c++ have come up with template meta progrmaming, and the dynamic nature of python also makes it metaprogramming.
@GustavoBandeira Mostly, no.
I'll try to replace Mathematica with Python now
You may probably know it, but there is SAGEMath.
5:03 AM
I can use the math functions on an environment with Python, I guess it will help me on that.
It is written in python, FWIW.
Yes.
It's syntax is also similar to Python.
What low level languange is worth learning?
C, for a forseeable future.
Yep. It's the one I'm studying.
There is a new one on the market 'D', but I am not sure how really improvement it is over C, except for some cosmetic changes.
If you are interested in Low Level Programming and have some funds, get yourself a microcontroller board so that you can write C/ASM programs and run them on raw hardware. It is a good exercise I believe.
5:08 AM
A board like Arduino?
Yeah
like Raspberry Pi
but they are too damn hard to obtain.
Well, I guess Arduino is easy.
I'm just not sure on Raspberry Pi.
There are others by beagle.
I've made an observation: The market on low level languanges seems to have lower activity than the market on high level languanges.
Is it true?
@GustavoBandeira No. ARM is the company which mainly made processors for embedded systems. For a long time, and even now I guess, its sales outstripped any of the other sales (Intel,AMD etc you name it )by a large large margin.
5:12 AM
There are more high level programmers than low level programers?
@GustavoBandeira Yes.
Ops, more low level than high level programmers?
No. I do not think so. Basically, even if you write one simple app for your desktop in bash, you are a high level programmer.
For low level programming on the other hand......
also, what happened in earlier days was C was the default language and hence, every thing you do was in C.
Stallman did emacs in lisp, but then he was stallman.
In Brazil, I guess that programmers make basically three kinds of software: Cellphone games/Sales controlling software and websites.
Since then, attention has shifted and a lot of choice of programming languages is there more suited for specific tasks and people have taken those.
5:15 AM
programming languages are too splintered (IMO)
Yep.
hey Jayesh, do you know makefiles?
@Jeff Yup, I know makefiles.
@JayeshBadwaik yup, that's the fact! That was certainly why the programming language APL was created (can anyone guess what "APL" stands for?).
5:18 AM
I wonder. Never heard of it I guess.
@Jay so there is a command, hostname, which returns a value (the name of the host). but hostname is not an environment variable. how do I get the result of hostname command into a makefile.
APL=___ Programming Language (guess what the missing word is)
@Jeff Okay. Now I get it. You are talking about A. Then there was B and then there was C.
yup, you guessed it before I even asked the question. :D APL is "A Programming Language" because it was supposed to be the last, all-encompassing, programming language, which could do what everyone wanted! :D
5:20 AM
@Jeff Use the command $(hostname) @JayeshBadwaik that didn't work. Jayesh, C has the feature of being compiled to assembly or binary (I don't remember), D has the same feature, right?${hostname} (I used braces) is for environmnent variables. I'll try parenthises
I discovered this some years ago when I tried to make a custom MIDI controller, I discovered I would have to build drivers.
@Jeff $(xyz) executes the command xyz and returns the result. 5:22 AM it didn't work. Did I do something wrong: thishost =$(hostname)
@GustavoBandeira Those are the blackhole of a programmer's time. Everytime you say "I work on writing drivers", other programmers would spontaenously get up and give you a consoling hug. "Hang in there bro", they would say.
and then: rcom-nodes 'rcp ${thishost}:/hom.... @JayeshBadwaik lol @Jeff You are trying to write a bash script, why are you doing this in a make file? @JayeshBadwaik Why? Is it so nightmarish? @GustavoBandeira Hardware is so so badly documented, you would think it was manufactured by wizards of hogwarts. 5:24 AM because it's part of a compile. after i compile, i have to copy the compiled file to all the nodes because we're having this (stackoverflow.com/questions/12167576/…) problem and the admin won't make the system change to mount "noac". With FOSS, the situation is improving, but there are a lot of blue patches. @Jeff I have a two-part advice. First is this quick hack. 24 I often find bash syntax very helpful, e.g. process substitution like in diff <(sort file1) <(sort file2). Is it possible to use such bash commands in a Makefile? I'm thinking of something like this: file-differences: diff <(sort file1) <(sort file2) >$@ In my GNU Make 3.8...

@JayeshBadwaik The idea was to use something like arduino to make it. Even with arduino it would be hard? - I built the impressions that arduino is well documented, but I have no basis for that.
yeah, it's a quick hack. but it's also the only option i have atm.
@Jeff the other option is to write a bash file to do all the stuff you want to do and then use makefile to run that bash file.
that can be done as simple as ./your-file
@GustavoBandeira Arduino is well documented.
how do i call the bash file inside make?
5:27 AM
Just like you call normal programs like gcc.
but then this time, you have that bash file in your specific folder, which is not a part of the $PATH environment variable and hence you would need to use the command ./your-file instead of just your-file @GustavoBandeira the goal of all the stuff of arduino, raspberry pi is to re-introduce people to low level programming, since actual real-world low level programming is now too complicated (in PC for example) @JayeshBadwaik Didn't know about that. It was reported at one conference that the code size of UEFI (the new generation BIOS) is larger than that of the linux kernel without the drivers. and UEFI does not include drivers of the system it is installed on! :P Some years ago I bought something similar to arduino, it's a brazilian project. - It's extremelly bad documented. =/ @JayeshBadwaik if that worked, then why doesn't the call to gethost work? is that not a bash file? gethost? sorry I must have missed a message in the conversation. @GustavoBandeira Ohh. Yup, working with badly documented project sucks. I fortunately had a well-documented on. It was a local project, the manufacturers were from my city only. @Jeff I guessed you did something wrong. 5:33 AM @JayeshBadwaik i meant to type hostname, not gethost. I can't install SymPy on my computer, it says I haven't python installer, But I got python 3.2.2, maybe I need the 2.7 @GustavoBandeira Yeah, that can be the stuff. I guess stuff hasn't been ported completely yet. @Jeff For that, I guess that questions provides a correct answer. The reason is the support of "$(something)" command
Jay, why do you learn math?
OK. I have this file which is not working:
thishost = $(hostname) rcom-nodes 'rcp${thishost}:/home/schwarz/sundials/instdir/examples/cvode/parallel/${EXAMPLES} /home/schwarz/sundials/instdir/examples/cvode/parallel/' the first line doesn't work. thishost remains empty @Jeff Try writing it as "export thishost=$(hostname)"
NO SPACES AFTER "thishost"
5:38 AM
didn't work
@GustavoBandeira I like math and I have fun doing it.
@Jeff you are inside a makefile?
You study some math topics beyond what you really need on your profession, right?
no. it's just a file called "copyfiles". those two lines are the only content. i changed copyfile to be executable.
Once you mentioned something about analysis, I guess you don't need analysis for electrical engineering, right?
@Jeff Strange. Just a sec. I will try that myself and get back.
5:40 AM
k
@GustavoBandeira Analysis is required in electrical a lot. Algebra and topology are not required much.
@gustavo you probably need some analysis for EE.
@Jeff Heavy analysis :P Not formal, not epsilon delta proofs, but the techniques.
I thought engineering wouldn't require analysis.
@Jeff It works for me
@GustavoBandeira Naah, stuff is too complicated now a days. Everywhere, you require all kinds of techniques.
Control systems is a direct outgrowth of complex analysis and calculus of variations for example.
5:44 AM
@jay something is wrong with the second line. i tried this: at the commandline i typed export thishost=$(hostname) then I typed echo thishost and it replied "node8". @Jeff Yup. hence, first line is working correct. 12 A first approximation is that real analysis is the rigorous version of calculus. You might think about the distinction as follows: engineers use calculus, but pure mathematicians use real analysis. The term "real analysis" also includes topics not of interest to engineers but of interest to pure... I thought it because Quiachu's answer. Then in the file, I deleted the second line, so all i had was rcom-nodes 'rcp${thishost}:.... and it still did not work, as if thishost was empty.
why won't it expand ${thishost}? is it because it's in quotes? @Jeff for env variables you just need to type$thishost
@GustavoBandeira One stuff is calculating all right. But then, even (or is it especially?) engineers need to provide guarantees that their formulas will work!
See the thing is too much stuff is too complex too be modeled analytical. So, to be able to choose good analytical models requires a lot of analysis background. A lot of info about how tight are the error bounds, how strong is the convergence and stuff. Much of the required experience is gained from a mathematician like study of analysis course.
5:48 AM
does it give a no such file or directory error?
what is rcm-nodes?
it says "Unknown host" over and over again.
what does it do?
rcm-nodes is a command which runs whatever is in quote on all the other nodes
okay
then you can see why that is a problem
I use rcm 'md5sum FPU' to check if all the files on all the nodes are the same.
5:50 AM
the environment variables are not transferred
ok, but isn't ${thishost} expanded before transfer to the other nodes? if not, how do i get it to expand first? I did not know the answer to that question. But now I guess not. and it is pretty normal I guess. so i need to find out how to make the variable expand before sending to other nodes. maybe i'll post it on stackoverflow (i mean if i can't find an answer by searching first - but i'm not sure exactly what to search on) @Jeff Yup. Or may be you can just hardcode your node hostname for now? yeah. that's kind of a lame solution. but i may have to do it. 5:53 AM @Jeff Sometimes good enough but lame is good enough! @jay that is so true :D Or may be you can try removing quotes and then see. I am not sure though. if i remove the quotes, then rcom doesn't work @Jeff ohh, thought so. hmm, may be you can expand the command before like this? export command=rcp${thishost}:/home/schwarz/sundials/instdir/examples/cvode/parallel/${EXAMPLES} /home/schwarz/sundials/instdir/examples/cvode/parallel/ And then run rcom-nodes$command ?
@JayeshBadwaik Yes, Installing Python 2.7.3 allowed me to install SymPy, yay!
5:59 AM
@jay that might work.
@GustavoBandeira good.