« first day (1749 days earlier)      last day (3289 days later) » 

10:00 PM
@Ramanewbie Lis Maurice Grevisse.
 
@hippa Ca depend certains exercices de maths te font reflechir au dela d'appliquer betement un eformule
@gato c'est qui ?
 
grammairien
 
@Catija, seems like plenty of answers there already.
 
@gato Ca date de quand ?
 
Moi, j'ai le livre de M Grevisse près de moi, @Gato.
 
10:01 PM
@Ramanewbie XXème
 
LOL
 
@TedShifrin There are, I just wasn't sure because using "minus" sounds off to me but my mathematics knowledge is pretty basic.
 
@TedShifrin I am impressed :D.
 
@gato C'est nul... Quel intérêt de lire des livre de grammaire ?
 
you're correct, @Catija. It should be "the negative" or "the opposite." One tends to use "minus" as a verb.
Il y en a entre nous des gens qui s'intéressant à la grammaire, @Ramanewb.
 
10:03 PM
@Ramanewbie Pour comprendre que la langue française n'est pas juste une juxtaposition de règles mais aussi d'une réflexion réelle.
 
syntaxe ... etc.
 
@Gato Quelle propertion d'élèves de Lycée savent redémontrer le th. de Pythagore ? Quelle proportion infime sait comment se partitionne les aires des carrés correspondants, et comprennent donc ainsi en profondeur le théorème ? :(
 
That's a pretty messed up square, @Hippa.
 
Et en attendant ils apprenent par coeur les formules des intervalles de confiance :/
 
@TedShifrin Ah, ok. Good to know.
 
10:04 PM
@TedShifrin That's paint for you
 
Thanks!
 
@gato @ted N'empêche, lire un livre de grammaire je pense que ça doit être assez ennuyeux... @hippa Would you read it ?
 
Of course, @Catija :)
 
@hippa I bet 65% ?
 
La structure du langage est aussi intéressante que la structure des maths.
 
10:05 PM
@Ramanewbie Il y a des livres de grammaire intéressants. Comme partout, ça dépend beaucoup du style de l'auteur
 
@Hippalectryon Combien d'élèves de prépa savent le faire ? :D
 
@Ramanewbie maybe roughly half for the first one and <5% for the second one
 
@gato 1/1
 
@Vrouvrou I have fixed the answer. Do you see why it doesn't really matter that $u\in C(\overline{\Omega})$?
 
@Gato Bonne question ! La géométrie a quasiment disparu du programme de collège/lycée/prépa
 
10:05 PM
@robjohn: Thanks for being the analyst to the rescue :)
 
@Ramanewbie Oh no :c not even close
 
@hippa That's not true. I did analytic geometry this year.
@hippa And vectors, and trigo.
 
@Ramanewbie That's not what I call geometry
 
Moi non plus.
 
@hippa What is it then @gato
 
10:06 PM
@Hippalectryon@Ramanewbie géométrie analytique :DDD
 
Les propriétes de la droite d'Euler par exemple
 
@gato Qu'est-ce qu'il y a avec la geometrie analytique ? Ce n'est pas bien ?
@hippa Je connais pas cette droite
 
C'est un moyen de transformer la géométrie en analyse
 
hi @TedShifrin and @BalarkaSen
 
10:07 PM
C'est très bien mais c'est aussi une approche différente. On perd un point de vue
 
altough he is probably sleeping balarka
 
ok, @Karim, so I'll leave to cook dinner :P
 
noo !!!
 
Balarka did finally go to sleep, yes.
 
10:07 PM
@Ramanewbie Réfléchir sur des dessins..
 
@Gato Réfléchir
 
@Gato: Les questions que je t'ai envoyées étaient bien trop faciles?
 
hippalectry
 
On réfléchit bien trop peu au lycée
@KarimMansour ?
 
just out of curiosity are you ted student ?
 
10:08 PM
@hippa Even when You were in Lycée ?
 
No, he's my enemy, @Karim. He's in Paris.
 
@KarimMansour No way, I live in France
@Ramanewbie Yes. It's nothing new.
 
oh I see
 
@hippa @ted He could be your student by correspondance...
 
@Karim: Only two of my former students are frequently here (that I know of).
 
10:09 PM
haha
 
One day we'll need to settle this with a pitchfork duel :c @TedShifrin
 
oh I see who are they @TedShifrin?
 
Or you could apologize, @Hippa.
 
@ted Who ?
 
@TedShifrin Pas difficile mais pas facile, surtout la dernière question. Mais c'est prévu pour combien de temps ?
 
10:10 PM
Kaj and CBjork
 
oh
yeah Kaj I should have logically deducted that
 
@ted @hippa For the 10th time Will someone of you explain me what happened between you two ???
 
L'examen finale = 3 heures ... le midterm = 1 heure.
 
@hippa (except that meme)
 
The meme I didn't mind ... it was all the extras.
 
10:11 PM
@robjohn whu the integral do not converge ?
 
@TedShifrin Well I can always apologize if you took all of that badly but my global point of view hasn't changed. We's rather not talk about that now anyway or it's likely to end up like the other time
 
well I thought he was student based on the meme he has I guess
probably some video in linear algebra or something
 
@ted Kaj hansen ?
 
@TedShifrin C'est presque comme nous donc. Demain c'est 3heures aussi.
 
There are 104 videos up on YouTube, Karim.
yes, @Ramanewb
 
10:12 PM
yeah :D
 
@hippa Pitchfork duel lol...
 
Nothing wrong with pitchforks @Ramanewbie
 
@ted So what happened ? Please don't tell : 'ask hippa !'
 
@Ramanewbie Why do you care ? That's none of your business
 
@hippa IDK...
 
10:13 PM
humans are curious creatures @Hippalectryon
 
@hippa That's the reason.
 
Good night @TedShifrin@Hippalectryon@Ramanewbie.
 
@robjohn ?? please
 
@Gato Good night !
 
night @Gato
 
10:14 PM
It appears @Hippa got carried away being a rude adolescent, @Ramanewb, so you should behave better and have a bit more respect.
bonne nuit, @Gato
 
Good night @gato
@hippa Why do you point at ted's message ? What do you mean ?
 
is it possible to prove Z(G) is subgroup of C_G(A) using group actions
 
@Ramanewbie You asked a question, he answered, I supported the answer. that's all
 
It's immediate from the definition. Who needs a group action? But, yes, you act by conjugation and ...
 
10:16 PM
Ok.
 
well yeah if you act by conjugation on G we have the center if we consider the kernel
and if we consider some subset of G and look at kernel we will get the center
 
Well, you need to define a different action for $C_G(A)$. Not that I'm sure what you mean by that. :)
 
It's late I should go to bed, too... Good Night @ted@hippa
 
Bonne nuit, @Ramanewb
 
@robjohn are you there ?
 
10:19 PM
well to get consider the set that G acts on as A $\in$ P(G) now $C_G(A) = kernel(gAg^{-1})$
that will give the centeralizer
 
@Vrouvrou What?
 
now if we consider all set G it will give the center of G.
 
i don't understand your last comment @robjohn
 
but that wouldn't prove that center is subgroup of centralizer however I know how to prove it its just some set theory inclusion but I was wondering can we get it directly?
 
the integral is finit so it is not good @robjohn
 
10:20 PM
from group actions @TedShifrin ?
 
Is $A$ just a subset of $G$, @Karim?
 
Then $G$ does not act on $A$ by conjugation.
Only if $A$ is a normal subgroup do you get an action.
 
but I am considering the kernel of that action.
I don't understand
 
LOL, but it is not an action.
 
10:23 PM
why
 
To have an action, you must map the set back to the set.
 
@robjohn what it means but each one is monotonically increasing to |x|α, so the norm in (2) grows without bound,
how to see this ?
 
oh I see
wait
I think I wrote the problem wrong
I am letting $N_G(A)$ act on set S = A by conjugation and it indeed normal
by definition
 
Oh, now you're doing the normalizer, which, by definition, maps $A$ to $A$. Yes.
So the center is the set of elements of the normalizer that act trivially, yes.
 
yes I forgot about that yes your absolutely right since an action is a map from GxA $\rightarrow$ A
that is one way to look at it or it is defined as the homomorphism from G to $S_A$ same thing of looking at an action
but yeah my question is can we now derive that center is subgroup of centralizer using group actions ?
 
10:26 PM
 
@Karim: That's what I said.
OK, I'm outta here. Have fun.
 
why u_n is monotone @robjohn
 
@Vrouvrou look at the function definition. $u_{n+1}(x)\ge u_n(x)$.
 
could someone give me a sanity check on something please (not exactly mathematics, but came up on MSE)?
 
10:31 PM
would you consider my initial comment to an answer as rude or inappropriate? (math.stackexchange.com/a/1286627/27978)
 
@robjohn right and please how we apply the theorème ?
 
ok that is what I don't understand @TedShifrin the center is yes trivial map since we have all kernel(G) is all of G but this proves that center is subgroup of G however not of $C_G(A)$. Maybe I am misunderstanding something
 
@robjohn when n goes to $\infty ,$ $u=|x|^{\alpha}$ right ?
 
no @copper.hat I don't think so
 
@KarimMansour: thanks.
(i am sure my other comments were :-))
 
10:34 PM
please @robjohn
 
@Vrouvrou well, it pretty simply follows from this comment and the fact that $\lim\limits_{n\to\infty}u_n(x)=u(x)$
 
well yeah I guess so @TedShifrin because one we will have that kernel of the map is all of G and the other we will get a subset of G so the map itself has less in the kernel has more elements so that is why the center is subgroup of the centralizer let me know what do you think of this reasoning when you come also you @BalarkaSen
 
@robjohn $u(x)=|x|^{\alpha}$ right
why we need the monotonicity @robjohn ?
 
@Vrouvrou so that we can apply Monotone Convergence
 
@copper.hat I don't think it was either. I'm not sure how it's relevant (or how you deciphered that vowel-less notation), but it certainly wasn't rude - merely a fact being stated.
 
10:38 PM
we use monotone convergence to obtain the limit u(x) ?
@robjohn
 
And the "relevance" comment was really just about my ignorance; not saying it actually wasn't relevant!
 
oh excelent
your here @pjs36
what do you think of my reasoning above ?
 
@pjs36: thanks! just wanted to have another pair of eyes. appreciated.
 
@Vrouvrou Look, if the $L_{p^\ast}^1$ norms of $u_n$ were bounded, the $L_{p^\ast}^1$ norm of $u$ would be finite. So the $L_{p^\ast}^1$ norms of $u_n$ must be unbounded.
 
@robjohn i stay don't see where you use the monotonicity !
1/n^{\alpha} tends to 0 when ntends to infinity so by the definition of u_n u_n tends to |x|^{\alpha} @robjohn
 
10:43 PM
brb cooking dinner
 
Monotone convergence says that since the $u_n$ increase to $u$, if $\|u_n\|_{L_{p^\ast}^1}$ increases to a finite value, $\|u\|_{L_{p^\ast}^1}$ will be equal to that finite value. Since $\|u\|_{L_{p^\ast}^1}=\infty$, we have that $\|u_n\|_{L_{p^\ast}^1}$ increases without bound.
@Vrouvrou NO... $\alpha\lt0$. Remember? That is what all of this is about.
 
ohhh yes sorry @robjohn
but when $u_{n+1}\leq u_{n}$
 
@KarimMansour I'm not sure I follow your reasoning above. Is the question just why the center of a group $G$ is a subgroup of the centralizer of $A \subseteq G$?
 
why u_n tends to u ?
@robjohn
 
I want to reason the center is subgroup of centralizer relying only on group actions @pjs36
 
10:48 PM
@robjohn are you there ?
 
so I am using $N_G(A)$ act on set G via conjugation and consider the kernel to get the center and for centralizer I consider S to be A some subset of G.
under same action
this will indeed get that they are subgroup of G but I am trying to reason as I reasoned above center is subgroup of centralizer
 
@Vrouvrou No $u_{n+1}\ge u_n$
 
yes sorry @robjohn
 
@pjs36
 
but how you obtain that u_n tends to u @robjohn
by defintion of u_n we have that u_n tends to \infty when |x|<0 which is impossible !
@robjohn
 
10:54 PM
@Karim So $N_G(A)$ is acting on $A$ by conjugation? I'm seeing a little more, but I would still be pretty surprised if you could prove this without... well, the basic definition, basically.
 
@robjohn ?
 
yeah but now we have a map given by group action one map that has the kernel of the action as the whole group G and the other has the kernel of the action as something smaller that is subset of G so the other map must be more surjective right?
 
@Vrouvrou Given an $x\ne0$, by the Archimedian property of the reals, there must be an $n_x$ so that $|x|\ge\frac1{n_x}$. For any $n\ge n_x$, we have $u_n(x)=u(x)$. By the definition
 
@pjs36
injective
I mean
I meant
 
If we have the expression $ax + 3$ how do we know $a$ is a parameter or a plain variable? Or must the assignment explain that?
I'm confused on the difference between constants/parameters/variables.
 
user128043
10:59 PM
1
Q: Geometrically, why do line bundles have inverses with respect to the tensor product?

Kevin Dong Geometrically, why do line bundles have inverses with respect to the tensor product? Here my thoughts on the problem so far, please excuse their scatteredness. I know algebraically, it is just because they are locally modules generated by $1$ element. Basically, it is just the fact that if ...

 
hm I don't knw
 
user128043
Can someone help with my question?
 
@Vrouvrou why are you worried about $|x|\lt0$?
 
I will think about it more when I prepared supper
 
11:40 PM
@KevinDong maybe @Ted can
 
Can anyone explain what contraction mapping is to me?
 
a map that always reduces the distance between two points
as a result, if you keep iterating it every point approaches some specific point. hence it 'contracts' to that point
 
Ah! That's brilliant.
Thanks @MikeMiller :D
 
Are you sure, Mike? I thought it was things like $(\text{can}, \text{not}) \mapsto \text{can't}$.
 
11:57 PM
False, @Mike @Stan
 
I'm sorry I didn't say that it always reduces the distance by a scale that's bounded above by some constant less than 1 because it seemed like that would probably make the concept harder to understand!
 
Lol, but crucial ...
 
not for visualization
in my opinion
 

« first day (1749 days earlier)      last day (3289 days later) »