Am back.

Hi : )

@Matt all the counterexamples I know in that area involve logs

@robjohn, I updated my answer in this question.

@Matt: It could work. On the other hand there is the classic bijection: $$A\mapsto\sum_{i\in A}2^i$$

[I have mentioned Bill's posts, although it's what you know already...]

@robjohn Nice. Then I'm happy.

Hi Matt.

Okay. I think it's about time we have a Chat Etiquette meta thread.

@AsafKaragila that also works, but I have seen both in the past.

@robjohn Of course, but that is a bijection.

@AsafKaragila why isn't the other a bijection?

@AsafKaragila This is nice because I don't have to find any primes.

@robjohn the subtlety is that the other isn't a classic bijection. :)

Yes, that too :-P

@tb I see. I will have to review my classic bijections :-p

@robjohn : )

Didn't you get the memo??

@AsafKaragila I was afk

The new book "Classic Bijections Through The History of Time" is out.

@AsafKaragila Elton John was classically trained...

I have a bottle of port which I am unable to open :(.

@JonasTeuwen Ask the girlfriend to open it for you?

Elton John is that guy who's Elton John, no?

@Matt Why would that help?

It is a special sealing.

@JonasTeuwen Push the cork into the wine and just drink it .

I think I'll have to saber it.

Or break the top part and drink carefully to avoid the shards.

@JonasTeuwen they know tricks. but many men are too macho to find out...

@JonasTeuwen I thought it worked both ways: if the gf can't open then they ask the bf and the other way around.

@tb This one does not. I have tried.

@tb Jonas' gf knows tricks?

@robjohn Apparently not (see line above)

@Matt It only goes both ways if the girl goes both ways.

@AsafKaragila I fail to make sense of that.

@Matt What sense?

@Matt that's good. That could be quite startling to come home to find a trick there.

@robjohn True. On the other hand, knowing tricks doesn't mean you have to use them. : )

Oh, I had to melt it open 8-).

Is this an ethernet port in a router?

@JonasTeuwen : O Interesting technique.

@AsafKaragila as long as it was not port 80, that would interfere with using a browser to get here.

Hell yeah, I've opened it.

Where is my chocolate 8-).

@robjohn That would be a TCP port, I was talking about physical ports.

Wow! What a wonderful idea: UPnP bottles!

@AsafKaragila you jumped the rails; so did I :-p

@robjohn Is this how Dylan came up with title Blood on the Tracks?

@tb I like your second sentence.

@Matt His second sentence ever? Probably something like "Mamma!" or so.

What is this obsession with your mother, @AsafKaragila?

@Matt That is not a part of my obsession about mothers. I don't think that the second sentence a baby says is probably not "Let $H$ be an infinite dimensional Hilbert space, and $\mu$ a probability measure on $H$...".

@tb Have you seen the TG talk before Todd Trimble deleted his post?

@AsafKaragila Yes.

Too bad meta.MO has a different software and you cannot see the edits, eh?

@AsafKaragila TG talk?

I have to leave now.

Not really. I think this Iyengar drama went out of hand a long time ago.

What's TG? I only know TGIF. Bye Asaf!

TGIF?

@AsafKaragila That would be wicked if a baby says that.

Thank G*d it's Friday.

It's about this thread

@JonasTeuwen Perhaps von Neumann said that, but I'm not sure there was someone else who could.

@Matt Why did you bleep G*d? Is it a new curse word or something?

@AsafKaragila I just don't want to use the word.

Wow, someone is asked not to ask any more questions on MO because they are too... strange?

TG = Trust G*d?

G*ddammit?

@tb Alex Bartel in that thread seems to imply that trustgod is Iyengar. Is that the Iyengar we have here?

@robjohn yes he is.

@robjohn Here and there.

I remember that I was perplexed when trying to deal with Iyengar.

Why?

@Matt I don't remember exactly, I was just glad when I wasn't dealing with them anymore :-)

Are you also perplexed when you have to deal with me?

@Matt no, you try to learn. I didn't get that impression from Iyengar.

phew : )

Descriptive title.

@Matt difficult to make sense out of, yes.

@tb Especially what $d(x_n-x,0)$ is meant to be, unless you give some group structure to R.

Someone's talking to himself :)

: )

For the harmonic analysts among you

That's more like PDO?

And I think he already gave the solution basically.

Right. But I can't resist mentioning that you have a very narrow interpretation of what is harmonic analysis and what isn't :)

The proposal for a separate Mathematica site was closed. However, due to community support, we have been given the option of opening a new one. Any help from this community would be greatly appreciated. Thanks.

@JonasTeuwen Now back to your port!

spam

@tb Sure thing 8-).

@JonasTeuwen There doesn't seem to be any evolution given in $\xi$.

@QED baked beans?

@tb Correct. The only harmonic analysis is the stuff I do. ;-).

@JonasTeuwen :-p

Hi!

I see that the middle terms form a serie, but I had some problems finding an easy solution for this

The problem above sort of says

$$ n! - \left[\sum_{k=0}^{n-1} (n-1-k)(n-1-k)!\right] - 1 $$

Do it by induction $$(n+1)! - \sum_{k=1}^{n} k \cdot k! - 0! = (n+1)! - n \cdot n! - \underbrace{\sum_{k=1}^{n-1} k \cdot k! - 0!}_{= - n!} = 0$$

So i just shows it is true when n=1

Yes.

assumes it holds for an arbitary n=k

and then shows it holds for n=k+1

Right. I just showed you the induction step.

why did you take it the "opposite" way?

I feel like you showed n = k - 1

My induction hypothesis is $n! = 0! + \sum_{k=1}^{n-1} k \cdot k!$

Thus $0! + \sum_{k=1}^{n} k \cdot k! = 0! + \sum_{k=1}^{n-1} k\cdot k! + n \cdot n! \stackrel{\text{IH}}{=} n! + n \cdot n! = (n+1)!$.

I got deworm tablets for my b-day. Nice : ) Nothing like having a vet as best friend.

I'm happy to read the second sentence :) For a moment I thought the : ) was a typo...

@robjohn Yes, that's much nicer. I should have known I was doing it in too difficult a way.

Although I liked the induction way too

Its good to practice that once in a while too

I should have remembered...

ah you used ((k+1)-1) k! = (k+1)! - k!

@QED that's the thing to see.

@robjohn Do you see a way how to move this \sim a bit upwards: $A \; \xleftarrow[\sim]{f}\; B$ produced by A \;\xleftarrow[\sim]{f}\; B

@robjohn very good, thanks!

It feels hackish, but it seems to do the job

It's good enough for me!

You could even try Huge instead of Large

Large looks better in the preview of the main site.

Hugh Laurie? Huge Largie?

@tb okay, I tried Large and Huge to make the superscript look more like the original

Huge is definitely bigger than the original

I need some advice on how to write some homework exercise. It's for freshmen, and I want them to show that some order on $\mathbb N\times\mathbb N$ is isomorphic to $\mathbb N$ with the usual ordering. However they literally have no actual tools to handle the mission.

Tomorrow morning it'll be better. Goodnight!

Good night folks, I'm going to sleep! See you tomorrow : )

@Matt good night

Good night everyone who goes to bed!

@tb later, sleep well

@robjohn I'll probably stay a while. But thanks!

@tb Oh, when you said everyone, I thought you were leaving, too.

I see you ammended your comment :-)

I saw the ambiguity, but too late :)

It is sometimes difficult to know whether "good evening" is a "hello" or a "goodbye"

similarly with "good night", but that is more usually a "goodbye"

Exactly. By the way: thanks, now I have this Beatles song in my head...

Should this question be migrated to stats.SE?

Is there a way to read the math people are writing here, i mean the code behind the math ?

Oh, show source...

@N3buchadnezzar If it's a single formula, right-click it and select "show source". Furthermore, at the end of a question or an answer you should have a link that says edit or improve this question. From there you can see the entire source (and copy-paste it if needed).

Yeah, I figured it out =)

@tb probably. A stats person would know the answer right off, I would think.

@tb Sorry about the Beatles song. I know the one you mean.

@robjohn Could you please vote to close as off-topic and choose the option migrate to stats.SE, then?

♫ You say "hello", and I say "goodbye" ♫

Aaaargh, it was almost gone !

@tb :-D

@tb done. we need three more.

Great, thanks.

Your class mate from grad school has this habit of posting nonsensical non-answers

@tb He was always a bit of an odd one.

@robjohn I can imagine...

@tb He was a Thurston student. I don't know if that says anything about him, but there were two I knew of.

The other was more normal. :-)

I came close to capping today. I got 200 points, but 30 was from acceptances.

@robjohn Well, I know someone who had the same advisor as Thurston and he's also somewhat odd. Maybe it goes all back to Evans?

It's the best I've done in quite a while :-)

@robjohn same here. 210 so far, but 30 from acceptances.

@tb could be...

@tb: you look as if you've capped to me :-)

You posted a couple I could understand that I hadn't looked at yet.

What is the blue number in a circle that comes up on the left side of my avatar but goes away quickly?

@robjohn Spam/offensive flags

@robjohn Thanks! You're almost capped now, too.

@tb Come to think of it, Thurston was a bit off the beaten track, too.

but I never really got to know him that well.

whoops wrong chat. Also what's up mathematicians!

@MichaelMrozek thanks. Is that something I should be doing, or something that I've said that someone thinks is offensive?