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00:11
@user1 Most honorable.
@skullpatrol hahaha
@Charlie :D:D:D
@skullpatrol :D:D:D
@PeterTamaroff Hello, sir.
@Charlie yipyipyip
00:15
@skullpatrol yipyipyip
@user1 What art thou ruminating about?
@Charlie Hehehe
@PeterTamaroff Hm. Dimension theory as one finds in commutative algebra.
@user1 No clue about that!
00:17
@Charlie Hihihi
I was wondering if you could explain to me how, in $\Bbb C$, $f\in C^1\implies f\in C^\infty$.
@skullpatrol hahaha
@Charlie Hohoho
@skullpatrol huhuhu
@Charlie Hyhyhy
00:20
@PeterTamaroff Hm. I would have to review some complex analysis, certainly.
@skullpatrol sometimes
@user1 Oh! Bummer.
@Charlie Also known as a "semi-vowel."
@skullpatrol :)
@Charlie Half the time it acts like a vowel.
00:22
@skullpatrol funny, isn't it?
In phonetics and phonology, a semivowel (or glide) is a sound, such as English or , that is phonetically similar to a vowel sound but functions as the syllable boundary rather than as the nucleus of a syllable. Classification Semivowels form a subclass of approximants. Although "semivowel" and "approximant" are sometimes treated as synonymous, most authors agree that not all approximants are semivowels, although the exact details may vary from author to author. For example, don't consider the labiodental approximant to be a semivowel, while proposes that it should be considered one...
@peter
@Charlie Yes?
@PeterTamaroff do you know set theory?
naive
@Charlie Yes, a little
00:25
@PeterTamaroff can you help me?
it's simple
but i can't think
I'll try.
Prove that (a,b) $\in$ P(P({a,b})) and a, b $\in \bigcup (a,b)$
more generally
Yes, I know what you're saying.
if a $\in$ A and b $\in$ A then (a,b)$\in$ P(P(A))
@PeterTamaroff :D
(a,b) = {{a}, {a,b}} both {a}, {a,b} are in P({a,b}) and so {{a}, {a,b}} is in PP({a,b})
00:28
We have that $a,b\in \{a,b\}$, yes? This means that $\{a\},\{b\}\in \wp(\{a,b\})$. Since $\{a,b\}\in \wp(\{a,b\})$, we have $\{a\},\{b\},\{a,b\}\in \wp (\{a,b\})$
@PeterTamaroff i get this part
i don't get the second
@Charlie {a} and {b} are subets of {a,b}, yes?
00:30
precisely
$\dfrac{1}{T} \int_0^T 0\,dt$
help with this integral
for the second part (a,b) = {{a}, {a,b}} and both a and b are in {a,b} so they are in the union set
@Charlie Well, then they are elements of P({a,b})
@PeterTamaroff subsets
@Charlie Nope. Elements.
$A\subset B\implies A\in \wp (B)$
00:31
1 min ago, by Peter Tamaroff
@Charlie {a} and {b} are subets of {a,b}, yes?
Use the definition.
The elements of the power set are by definition subsets of the original set
@Charlie Yes. But {a},{b} are elements of the powerset of {a,b}-
@pourjour What is the average of zero?
nevermind
00:32
@MichaelGreinecker 0
@PeterTamaroff I get it, pedro
@Charlie OK, perfect.
Let's move on then.
@PeterTamaroff but you forgot S
We have then that {a},{b},{a,b} are elements of P({a,b})
i got this ages ago
00:33
This means that {{a},{b},{a,b}} is a subset of P({a,b}), yes?
@PeterTamaroff yeses
Well, then (a,b):={{a},{b},{a,b}} is an element of PP({a,b})
@MichaelGreinecker but if used the theorem we find $=\dfrac{1}{T}[t]_0^T$
@PeterTamaroff of course
@poujour "the theorem"?
00:35
@Charlie OK. Then what is your question?
@PeterTamaroff i got it already, thanks :D
@MichaelGreinecker I means the rules to calculate the integral
@pourjour But you have 0 as a multiplier.
@Charlie Good.
@pourjour, that's for the integral of 1 (aka x^0), not for 0.
00:36
@skullpatrol no it's 1/T * (T-0)
7 mins ago, by pourjour
$\dfrac{1}{T} \int_0^T 0\,dt$
quick meta- question
sorry sorry I'm totally wrong
would it be acceptable to post my important edit on this post math.stackexchange.com/questions/365152/… as a second question? or is it better left in this one
I added it as an edit, because it shows why I'm asking the first question, but essentially asks a second question about a different integral
@Argon NO! NOT YOU!
00:44
@PeterTamaroff Hm? :)
@Argon "(removed)"
@PeterTamaroff Ah. I commented, but then the page updated suddenly and noticed my comment was no longer valid.
@PeterTamaroff YES, AARON!
@Argon I'm reading about the CR equations.
Do you happen to know why in $\Bbb C$; $f\in C^1\implies f\in C^\infty$?
@PeterTamaroff Nice!
@PeterTamaroff Sorry, I don't know :/
Are you learning complex analysis now?
00:51
@Argon Not really. Just studying from Apostol's Mathematical Analysis, and he works with the CR eqs a little bit.
HI @PeterTamaroff I think that follows from the Cauchy integral formula - you need more power than just the CR equations (if I remember correctly)
Why isnt the concept of set generalized to multisets? some people say that the mathematical object set is the most basic thing in math but we can't even make it represent the roots of (x+2)² = 0
@OldJohn Oh, I wasn't insinuating the CR implied those. Just asking why?
@nerdy It is. We just don't really need it that much, I guess?
it is ?
The books doesnt mention a set of being a specific case of a generalized mathematical object, the multiset
they introduce as different things
@nerdy You can distinguish elements in a "multiset" if you want by indexing them like $(-1,a),(-1,b)$.
00:57
@PeterTamaroff OK - but it is interesting that the proof requires something like the Cauchy integral formula
Where $a,b\in I$ some indexing set.
@OldJohn Sure!
@nerdy Don't worry.
hmhmhm is there any difference between families and multisets ?
i heard family is just an ordered set
A family is a set whose members are sets indexed by a set.
@nerdy Are you talking about indexed families?
@PeterTamaroff I answered a Q about something similar a while back
00:59
@nerdy Careful. The term "ordered set" has a very precise meaning.
It is a set $S$ where a (partial) order has been defined.
If you like it, a pair $(S,\leq)$.
hmm i see so they are all sets
interesting
AFAIK, a multiset does not need an index set.
@user1
Could you explain to me the formal difference between a class and a set?
@PeterTamaroff A class specifies which sets satisfy a given predicate $\varphi$ with one variable free, of course.
A proper class violates the axioms of set theory in some manner.
@user1 What is a proper class?
01:05
a proper class just means that it is a class i.e. is defined by a formula but cannot be a set
for instance the class of all sets is a proper class
@PeterTamaroff Deven's example is inconsistent with the axiom of extensionality, for instance.
@DevenWare A proper class is a class that is not a set?
@PeterTamaroff yes
Then what do we do with them, if they mess up with our axioms?
well we just cannot use them like they are sets
the objects inside the class may still be useful
for instance the ordinals are extremely useful
but the "class of all ordinals" is a proper class so we can't do much with it
01:10
Sometimes I read "the class of all continuous functions over some domain D"... are they talking about classes or use the word "class" just because?
It is definitely a set.
just the word
Yeah, I figured.
its contained in some amount of power sets of D
so it is a set. outside of set theory most people say class just to mean collection without worrying about anything
in set theory is the only time where they really distinguish between them
How is the word "classification" used in set theory?
01:15
is that all correct?!
@pourjour Context might help.
Crap. I downvoted and now my day rep is $-1$.
My weekly rep is 666.
MUAHAHAHAHAHA @OldJohn you there?
@PeterTamaroff yep
Always knew you had some connection with the devil :)
@OldJohn Apostol says that $f$ complex is diff at $z=c \iff$ there exists a continuous function $g(z)$ such that $g(c)=f'(c)$ and $f(z)-f(c)=(z-c)g(z)$. $g$ is just $\dfrac{f(z)-f(c)}{z-c}$ for $z\neq c$ and $f'(c)$ for $z=c$, yes?
He kinda uses this in disguise to prove the CR eqns.
maybe that would help
@PeterTamaroff sounds plausible, yes
@OldJohn I mean, I cannot think about any other possible candidate for $g$.
All I can think of is endowing a group structure to a set.
what is the other condition to prove that aa decreasing sequence is convergent ?
01:37
@pourjour Bounded below.
A decreasing sequence is convergent $\iff$ it is bounded below.
@PeterTamaroff you mean $U_n \ge U_0$
@pourjour I mean there exists some $A$ such that $U_n\geq A$ for each $n$.
@PeterTamaroff ok thanks
(of course all this is in $\Bbb R$)
@pourjour This condition that you wrote would make your sequence constant btw.
01:40
@user1 how?
@PeterTamaroff did you see the last integral I grave you?
@pourjour No, sorry.
thanks for your time
@pourjour Since it is decreasing $U_n\leq U_{n-1}\leq\dots\leq U_0$. So when $U_n\geq U_0$, you get equalities.
@user1 hmm thanks
@amWhy - I have a question about an answer you gave if you're available.
01:49
@Terabyte Sure...but will you upvote it? ;-)
Seriously...go ahead.
@Terabyte ask away
Hehe... ok. You wrote: Then A⊂B,A⊂B, but C⊈B and B⊈C.

Is this correct or should it be: Then A⊂B,A⊂C, but C⊈B and B⊈C.
Yes, what you write is that because there are sets, A, B, C (and provide an example) such that A⊂B,A⊂C, but C⊈B and B⊈C, the original implication is not true. That doesn't mean the implication is always false, but that it is not true.
@amWhy Ok, thanks for the clarification. I suppose I can give you that upvote now for the prompt reply ;)
@GustavoBandeira Wow...15 upvotes and counting. I'm impressed!!!
01:56
@amWhy I transfered one question from here to there. Because I thought the question was really interesting.
@Terabyte I thought you were going to accept my answer, Terabyte ? ;-)
@amWhy I did and then I apparently unaccepted it. Sleep deprived + caffeine overload = click happy. :P
@Terabyte I understand where you're at...been there!!!
02:14
@amWhy I will be posting another one shortly if you want first crack at answering it :P
@Terabyte Okay! ;-) I'll try and stay awake!
@Terabyte I saw you have two unanswered questions. Are you still looking for / in need of help with those?
@amWhy I actually was able to solve them but feel free to post any useful tips you have - I wouldn't mind seeing how you solve it and I'm sure someone else would find it useful in the future.
@Terabyte True...It's too bad that questions aren't addressed, at times...not that the interest isn't there, just a timing thing...and the onslaught of new questions...
@amWhy Yeah. I was a bit slow to reply when people were asking me how much I'd completed which didn't help matters.
@Terabyte True... I know I'm always surprised when I encounter questions that I would have answered, but missed, and i'm on a lot...For both asking and answering, there's sort of a "luck of the draw" ... timing wise.
02:23
@amWhy By the way, do you know how to get the formatting right for matrices?
@amWhy Hehe, understandable. I'm amazed that people seem to keep track of questions as well as they do - I was a bit skeptical that I would be able to get much help on this site but I've been very impressed with you lot so far :P
$$\begin{pmatrix} 1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9 \end{pmatrix}$$ for parentheses, {bmatrix} for "bracket" matrices.
@amWhy Nifty, thanks.
@Terabyte Glad to hear. I worry sometimes that users initially encounter a bit of an unwelcoming start...not knowing the "ins and outs" of how to ask, or the "culture" in terms of what's here...some users/answerers come down hard on new users/OPs.
@amWhy Yeah. I looked at a good 20-30 questions that had been posted and answered before I began posting. I was trying to avoid embarrassing myself too badly and I was trying to phrase things in the best way possible in order to optimize my chances of having the question answered.
@Terabyte Good for you. I felt the same way about answering...I "watched" on the side-lines for virtually three months before "jumping in."
@Terabyte Admittedly, I'm less timid about answering than I am/would be about asking questions!
02:37
@amWhy Heh. Yeah. I actually hate asking for help. Too darn stubborn. Which is actually why I typically seek help online - no one knows who I am (hopefully) :P
@Terabyte hehehe...It takes courage to ask for help, face-to-face, or on-line. I know for me it does... But my curiosity and interest win over my timidness...I'm like a kid that way...I can't squash my enthusiasm, so I jump in and ask. You'd be surprised how receptive professors/teachers are to questions. The only time to worry about asking a question is if you haven't thought at all about it.
Chances are, if you're really stuck, or questions emerge from what you're learning, there are many others with the same questions...and many who would have never even thought to ask...(because they don't know the material well enough to even have a question!)
@amWhy Yeah, part of my problem is most of my classes have 300ish students and I'm NOT brave enough to ask questions with that many people around. Of course I could always go to the teacher's office hours but they always seem to be when I have another class or am at work... and that's why sites like this are so awesome.
and I just posted another question a minute or two ago if you're bored :P
02:56
Dense set IN a topological space, (X,t). Is it simply for a A \subset X show that every x \in X is in A OR is a limit point of A ?
Yes.
Equivalently, show that the closure of $A$ is the space $X$.
I'm just asking because wikipedia says A \subset {of the topological space}
wanted to know if my proposed definition was the same thing
Oh, thanks for that @user1 !
So showing that the set of natural numbers is a dense set of (R,t) does not depend on the topology?
in (R,t) *
It certainly depends on the topology.
hmmm..
In the discrete topology, for instance, no set besides the space is dense.
02:59
Is ee.
I see*.
03:16
@amWhy thanks :P. I thought that's how it was done but I've never liked matrices and couldn't believe it was that simple.
@Terabyte took me forever to format, my apologies!!!
@amWhy Hah, don't apologize for that! Well worth the wait.
@Terabyte That's what's nice about proof by induction with matrices...it usually boils down to having to multiply only once...
@amWhy You still have a hanging parenthesis in the last matrix.
@user1 OOps that's my trademark...those darn parentheses!
03:26
I feel bad. I keep undoing upvotes on accident...
@Terabyte That happens...it's easy to do, inadvertently!
03:44
@amWhy When can describe the rotation of the object with $\pi$ rad, why not $\pi$ alone?
nvm, I found the answer.
@GustavoBandeira $\pi$ rad is $\pi$...rad just indicates "radians"...as opposed to $180^\circ$, which is $180$ degrees.
Yep.
Is it viable to indicate a rotation as Pi - meaning that it would be a rotation of 360 degrees?
@amWhy I forgot...are you a college student?
@Parth Sort of...hopefully on the way to earning my PhD
03:52
@amWhy What's your age?
Oh wait... wrong question
@Parth ;-)
@Parth did you recently change your username?
@amWhy Yes.
@Parth Hmmmm...now I'm curious!!!
pen, Ethereal, Novice and Dumb Cow are all me.
OHHHHHH...I know all those!
03:55
Yeah, the infamous guys :-)
@Parth Or I should say, I know all of you's
@amWhy Ha, right
@Parth Didn't realize you were one and the same...or else you have a bad case of MPD ;-)
Real quick question... if I were to form a function $y=x^0$, does this function have any points of discontinuity? Wolfram Alpha says it is continuous
but I don't think that's right (for $x=0$, we have an indeterminate form)
I decided to use my first name as the username instead of thinking of wise names every month.
03:58
@Parth Good for you...my first name is "embedded" in my user name.
@amWhy Yeah, you told me. Amy
@anorton I think it's more of a removable discontinuity.
@amWhy Your name is Amy? How cute!
@Parth Okay...can't remember everyone who knows!
@amWhy But I realized that much before, when you signed "amy" in one of the posts.
@GustavoBandeira Thanks...in Spanish class my name was "Amada"
04:00
@anorton The graph is wrong on that page, so I suspect w|a did not interpret "x0" to be "x^0".
@amWhy Last time you told me that it's easy for you to get ashamed, isn't it?
@Parth Yes...there are a few very old posts with my first name. And the post I put on meta, for congratulating Brian M Scott...I signed off as "Amy"...
@amWhy I was exactly talking about that one ;-)
@GustavoBandeira Yes, it is very easy. Should I be ashamed of my spanish name...it was given to me...
@amWhy I would love to be near you. I like people that get ashamed easily. :P
I think it's cute.
04:03
@GustavoBandeira I do too!
I think "Amy" is cute, yeah
So, amWhy is something related to Amy Whining?
Maybe Amy Whinehouse.
@GustavoBandeira "a" is pronounced as "a"... "m" is pronounced as "m"; what letter is pronounced as "why"?
@GustavoBandeira No...it can be taken as A + M + (letter that sounds like "why")
@Parth You got it!
04:05
Yep. I was trolling with my sensual sense of humor.
I also love the word "why"
@GustavoBandeira :P
@amWhy why?
But do you ask why you love why?
@Terabyte hahahahaha
@amWhy You told me :-P
04:06
$$\sum_{f(p)\equiv 0 \text{ mod a}}\frac{1}{p^s}=\frac{1}{s-1}\sum_{f(xy)\equiv \text{ 0 mod a}}_{1\leq x\leq a}_{1\leq y\leq a} \sum_{n}\frac{\mu(an+x)}{(an+x)^s}+O(1)$$ For any polynomials $f(x)$ with integer coeifients
@GustavoBandeira Yes...and I ask whyAmI...and I ask why not?
@Ethan Ethan always bombarding us with huge formulas.
@amWhy What if you're actually me?
@GustavoBandeira I think Parth would more likely be amWhy - I hear he has MPD.
Did you know that sometimes this kind of question actually make sense in my head?
(or she)
04:08
I feel like there's something weird in we being unable to transcend to other people's bodies, there's something weird in we being unable to be some other person.
And the most nice fact: I'm not stoned nor drunk when that becomes plausible to me!
@Ethan What is this?
NT?
It is what it is, on both counts.
@user1 That's conspicuous.
@Ethan This reminds me of my childhood. Whenever I got a flu, my father came with an injection.
In the buttocks.
04:12
lol tmi
I ran like Usain Bolt.
I got a deep trauma with that.
When I was 15, a scorpion stinged me.
I went to the hospital and they tried to give me an injection.
I refused.
:P
One medic tried to convince me, he said that a mutation could occur...
What came into my mind?
I don't get it
What you don't get?
What do I need to study to go to measure theory?
measurements
:f
@Ethan Oky. I'm able to measure my size.
What else?
04:17
I don't know lol what is that analysis
I don't know too. =/
A tiny bit of topology would not hurt, and some elementary set theory would be helpful. However, I cannot really think of any prerequisites.
What's it useful for?
Yes, I know that there is wikipedia, but the explanation is not made for noobs.
why do you want to learn it?
Well. My dream is to learn all mathematics.
6
04:21
lol good luck with that
there is alot of crap out there
But I know that it's dumb, then I'm chosing where towalk.
@Ethan Crap like my questions?
And how do you even define what "all" mathematics really is
oh well
@GustavoBandeira no lol alot of crap as in alot of math
not that its crap, just emphasizing there is alot of it out there
Like ultrafinitists?
I've heard they suck.
I shouldn't comment though I have only been studying mathematics for about 4 years
atleast outside of school
@Ethan I really started this year.
I spent a lot of time ashamed of asking.
04:23
@GustavoBandeira Well, we have intuition for sizes (as in length, area, etc) of sets, but there is obviously need for formalism (what is the size of the cantor set?). This is what measure theory offers. It also proves to be a good analytical tool (but I am not an analyst myself unfortunately).
I envisioned MSE users as demigods that would punish me for being stupid.
@user1 Area of sets?! WTF?!
@GustavoBandeira In Euclidian 2-space, I am pretty sure you have intuition for the areas of figures. (Elementary geometry).
04:25
That's all I mean.
Oh. Got it
Got it.
Gotit.
Gottits.
Got tits.
:9050589 What you mean?
Perhaps he was referring to some actual crap.
It seems the equation is not necessarily crap (pragmatically speaking), but the church of scientology transformed it in something that must be followed blindly.
@GustavoBandeira lol I don't know enough astronomy to interpret any sense of its value
Or biology
04:31
Well. We know that life is very rare.
Inteligent life must be much more.
Lemme show you something.
I assume there must be a little, atleast for detecting the conditions possible for life to be sustained
Speaking of sustaining life and detecting conditions: nasa.gov/mission_pages/kepler/news/kepler-62-kepler-69.html
@skullpatrol See? I'm not intelligent. My proposition that intelligent life is scarce is true.
6
Q: Does Fermi's paradox imply that civilizations will self destruct inevitably in a short time?

Sklivvz We should be able to estimate the number of detectable extraterrestrial civilizations in the Milky Way galaxy according to the Drake equation: By plugging in realistic values we obtain the result that there should be other civilizations in our galaxy, and this is what fundamentally motivates...

Look, Ethan.
10
Q: What elements are a possible basis for life?

Gustavo BandeiraI've been told that life on earth is carbon-based, Then I got curious about one thing: What are the possible bases for life and under which circumstances could lifr based on other elements exist? If the existence of a silicon-based life is possible and if it is, under what temperature, pressure...

There's a field: astrobiology.
subfield
04:36
I just don't know if they're trolling.
sounds very specific
@GustavoBandeira We should all use one language
@Ethan Agreed.
lol
skip to 1:40
04:41
lol ronald reagan versus the hippies is a recomended video

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