Mathematics - 2012-08-22 (page 2 of 2)

user19161

22:00

I think I liked it in high school though. After that, I pretty much felt it was a random collection of problems.

user19161

That's just my feeling. Of course, I know nothing about mathematics.

2

Gustavo Bandeira

@JasperLoy What do you like?

user19161

@GustavoBandeira I love real analysis.

Gustavo Bandeira

@JasperLoy I've heard about, but I have no idea of what it is.

Jacob Schlather

Have you heard of calculus?

3

Gustavo Bandeira

22:10

@JacobSchlather Yes. (If you're talking to me)

skullpatrol

hi @robjohn

Jacob Schlather

Real analysis is to a large extent calculus with much more rigor

Gustavo Bandeira

@JacobSchlather I guess that Calculus is the Michael Jackson of Math - Everybody knows it.

At least superficially

skullpatrol

And just like Michael Jackson its features change ;-)

2

Gustavo Bandeira

@skullpatrol lol

robjohn

22:13

@skullpatrol Hey there

Jacob Schlather

Anyway I think i'm going to head home, later everyone.

skullpatrol

later

Gustavo Bandeira

I remembered of the answers I gave on some math questions when I was younger:
"Find the length of side b in the following triangle:"
Ans: I have no idea.

skullpatrol

@GustavoBandeira If Calculus is the Michael Jackson of math that would make Algebra = Elvis Presley :P

Gustavo Bandeira

@skullpatrol Step on my blue suede variables

Old John

22:25

and john cage would be Category theory (a.k.a. Abstract nonsense)?

skullpatrol

Who would be geometry?

Pink Floyd??

Gustavo Bandeira

@skullpatrol Black Eyed Peas.

@OldJohn Almost all composers from 20th century would fill the purpose. Haha

Old John

@GustavoBandeira apart from Sibelius :)

skullpatrol

Now that screams geometry.

Gustavo Bandeira

Lots of platonic solids...

Abstract Algebra

user19161

23:05

Yay! I have 1800 rep now. 200 more to go to 2k and I can retire from MSE...

2

Old John

@JasperLoy yep - I'm thinking of retiring too - starting to seem a bit pointless

user19161

@OldJohn I am here mostly because I am not doing any real stuff currently. :-) But the best thing about SE is that I made many new friends, all my bros!

Henry T. Horton

Not me

skullpatrol

I past pointless ....

Old John

@JasperLoy yep - if I retire, I might still visit chat sometimes :)

user19161

23:08

@HenryT.Horton What? I am not your friend? pouts

Old John

(unless Henry is around!)

Henry T. Horton

@JasperLoy I have no friends

user19161

@HenryT.Horton I am with you always, even to the end of the world.

Henry T. Horton

I'm going to end your world.

skullpatrol

now, now gentlemen let's not get too emotional

2

user19161

23:09

@HenryT.Horton My real life has not even begun.

Henry T. Horton

I'm a woman.

user19161

@HenryT.Horton Really? OK, good for you. Maybe you will be my girlfriend some day...

Henry T. Horton

I'm a lesbian.

4

user19161

@HenryT.Horton Really?

user19161

@skullpatrol Really?

Old John

23:15

@HenryT.Horton I would star that - but it needs the context :)))

user19161

@OldJohn It might be a true statement, only "Henry" knows.

Old John

@JasperLoy absolutely!

skullpatrol

@JasperLoy So you have 21,872 rep on English Language and Usage and you want to retire after only 2,000 rep here. Does that mean you're 10 times more interested in English than Math?

user19161

@OldJohn But everything I say in chat is real.

Old John

@JasperLoy I always assumed so

user19161

23:18

@skullpatrol Well, I will return at a later point in time, perhaps.

Jayesh Badwaik

@JasperLoy you are leaving?

BTW, finally we have some new stuff on the starboard

user19161

@JayeshBadwaik Not really, I was just saying that I might stop trying to earn points after getting 2k.

user19161

I now have 14 stars on the star wall, this is a new record!!!

Jayesh Badwaik

@JasperLoy hmm,
@HenryT.Horton A lesbian named Henry, that'be new.

And look at @JasperLoy willing to travel halfway around the world for "a" girlfriend. :P

@OldJohn 205 reps in a day. It takes me months to earn that. I am only interested in questions I cannot answer. :P

user19161

@JayeshBadwaik It is my plan to go there for grad school, but I need to take care of some things in life first which might never happen. But I pray I will make it there in some years' time.

Old John

23:23

@JayeshBadwaik actually 215 - and the one I really expected a vote for got zero ;)

N3buchadnezzar

Heya =)

skullpatrol

hi

N3buchadnezzar

Anyone mind giving me some quick answers regarding elementary set theory ?

user19161

@N3buchadnezzar If it is really simple, shoot.

Jayesh Badwaik

@JasperLoy Okay!! Best luck dude.

N3buchadnezzar

23:25

@JasperLoy You are awesome =) Helping me with all my sillyness

math.ntnu.no/emner/TMA4145/2012h/exercises/oving1.pdf

I am wondering about question 1) with 5-7. We have not had our first lecture yet, but I wanted to try stay a tad ahead.

$S \cap B = 12 + 3 = 15$ ?

Jayesh Badwaik

5-7?

Henry T. Horton

5-7 = -2

According to Wolfram Alpha

Jayesh Badwaik

@HenryT.Horton ohh right, been a long time since I done that. thanks

:-)

skullpatrol

5-7 = -2 because 7 + (-2) = 5

N3buchadnezzar

I think my biggest problem is to learn the notation. What does $S \times B$ mean? And $S \backslash B = 0$? Since there are no elements in B that is not in S ?

user19161

23:30

@N3buchadnezzar I don't even know what a pack of poker cards looks like but I will tell you the set notation.

Jayesh Badwaik

$S \times B$ is the cartesian product

that is set of all $(s,b)\ s\in S \ b\in B$

user19161

@N3buchadnezzar In 5, that set is the set of all elements in S and not in B.

Jayesh Badwaik

and $S \ B = \{s: s\in S \ , s \not\in B\}$

user19161

@N3buchadnezzar In 6, that set is the set of all ordered pairs (s,b) with s in S and b in B.

peoplepower

For instance, the $x$ with $x_s=spades$, $x_v=1$ is an element of $S$ but not and element of $B$.

user19161

23:34

@N3buchadnezzar In 7, that set is the set of all ordered pairs in D cross D such that x=y.

N3buchadnezzar

confused

Henry T. Horton

I'll order those double D pairs

3

Jayesh Badwaik

@HenryT.Horton They are crossed :-/

Henry T. Horton

:(

user19161

@N3buchadnezzar Hmm, I think you should pick up any book on elementary set theory and have a read first if you are confused.

N3buchadnezzar

23:36

@JasperLoy The books are in the mail =)

peoplepower

Yes, this exercise seems to be intentionally confusing to someone just learning those operations.

user19161

I really hate using poker cards. I don't even know what a pack contains!

3

Jonas Teuwen

Nah, easy to understand. Just needs to check a bit on wikipedia.

Jayesh Badwaik

@peoplepower or they are just providing an early introduction to cartesian products?

peoplepower

@JayeshBadwaik I was thinking giving each $x$ two components already is not very helpful.

user19161

23:39

@HenryT.Horton For yourself?

Jayesh Badwaik

@peoplepower may be

@JonasTeuwen Hey dude, I did not get this.
"Also, I want to hook some stuff before executing of files during a ./configure. "
Why do you need a configure more than once?

Jonas Teuwen

@JayeshBadwaik I do not. Fixed it by seding it. It is when the toolchain bootstraps the just built binaries.

N3buchadnezzar

So... $S \times B = (3\cdot 4) \cdot 3 = 36$ ?

user19161

@n3b For example, if A={2,3,5} and B={1,3,7}, then A\B or also written A-B is {2,5}.

Jayesh Badwaik

@JonasTeuwen Right, that was what I was thinking.

@N3buchadnezzar Ordered pairs
$S=(0,1)$ $B=(2.3)$ then, $S \times B = \{(0,2),(0,3),(1,2),(1,3)\}$

user19161

23:42

@n3b Using the same A and B as above, A cross B would be the set {(2,1),(2,3),(2,7),(3,1),(3,3),(3,7),(5,1),(5,3),(5,7)}.

user19161

@n3b Note that ordered pair means that for example, (2,3) is different from (3,2).

user19161

@n3b And finally any condition to the right of the | symbol just serves to restrict it to a smaller set.

N3buchadnezzar

@JasperLoy I see! I will take a closer look at this tomorow

Jayesh Badwaik

@JonasTeuwen I have used weak forms of derivatives a lot of times for my finite element thing. Just today realized all the formality rests on the shoulder of Riez representation theorem and sundry.

user19161

@N3buchadnezzar Yes, like I say any elementary set theory book should cover all these in the first chapter. It's really simple, just need to know the notation.

Jayesh Badwaik

23:48

I knew it had to rest somewhere, now I know where.

N3buchadnezzar

Yeah, I look at the symbols and they confuse me. Once I figure them out I guess it will be simpler.

1:49 AM atm

Jonas Teuwen

@JayeshBadwaik Hmm... which Riesz? Riesz-Fischer?

user19161

@N3buchadnezzar I thought these would have been covered in the calculus course you took already.

N3buchadnezzar

@JasperLoy No, only limits, integration, series and so forth.

Jayesh Badwaik

@JonasTeuwen Royden says only riez which guarantees the existence of functional $F = \int fg$ on $L^{p}$ $p \neq \infty$

N3buchadnezzar

23:51

Epsilon/delta, abels theorem and so forth.

Jonas Teuwen

@JayeshBadwaik For the duality...?

Do you need Riesz for that...? What.

Jayesh Badwaik

@JonasTeuwen Well, now I looked up Riez Fischer, I guess I need both.

I am not yet studying that stuff, just reading ahead in Royden.

Now just concentrating on Lebesgue measures.

But there is an inner-product that has to be minimized in FEM

and we present that as a functional

user19161

I think Royden is a terrible book. Folland and Rudin are the way to go.

Jayesh Badwaik

and the authors always said for the functional to exist, the weak form of derivative must exist

user19161

I am now confused with @OldJohn avatar beard and @skullpatrol avatar hair.

Jayesh Badwaik

23:54

@JasperLoy I tried Rudin. He uses a rings of sets and I thought they might interfere with my algebra rings.

Jonas Teuwen

@JayeshBadwaik An inner product with one part fixed?

Jayesh Badwaik

@JonasTeuwen Yup

@JasperLoy and I am finding Royden okay as of now. Any specific criticism you have in mind, I can look out for that when I encounter it then.

user19161

@henry is really confusing me. One moment I think he is a guy and the next I think he is a girl. One moment I think he is into guys and the next I think he is into girls.

peoplepower

@JasperLoy Right now, though, you think henry is a guy?

Jayesh Badwaik

@peoplepower oh c'mon this is like the length of chinese emperor's nose

Jonas Teuwen

23:59

@JasperLoy Henry is too stressed up about the PhD and all that he has to resort to trolling. Give the guy a break 8-).

Transcript for

$Mathematics$ Mathematics