@robjohn Not really. I think I told you already: I haven't posted a single answer in days. I don't feel like going after the lhfs these days, and the remaining questions are hard. =)

@Brian Do you know what happened to Robin Chapman? Did he leave this site or is he an occasional contributor? Was some specific incident to blame? Context: the new meta post.

Google says lhfs stands for Land/Home financial services (that leaves me wondering, if math.SE borrowed some money)

Context: the new meta post.

@Srivatsan Ah, I am perhaps less picky. I don't see anything wrong in answering an elementary question. Low hanging fruit can still taste good :-p

@robjohn Oh, I live on them. =) It's just a phase were you are bored answering those questions.

@Srivatsan But you're right, there is a better feel to having answered a nice meaty question.

@Srivatsan I think that he’s gone. Wasn’t there some mention of that in the Jeff Atwood thread that we looked at the other day?

@BrianMScott Someone left the site due to a disagreement about how to post comments? That is a bit unfortunate.

Wasn’t that about high-handed removal of comments?

Wait, I didn't know RC was involved in that thread.

Here comes @anon!

I thought that I remembered seeing his name mentioned as someone who had left, if not in response to that incident, then for similar reasons. But I could be misremembering.

Hi @anon!

Hey. Just read about Bill n Willie.

Springbank 10 <3.

@Srivatsan I forwarded that link to Bill. I hope his head doesn't inflate too much :-)

@anon not fun.

@Srivatsan RC was mentioned, but not in connection with the current issue.

@robjohn Current issue=?

@Srivatsan The isssue between Bill and Willie

@robjohn Well, I did not say that there is any connection or parallel to RC. I knew RC is inactive here and didn't know why (I thought he is busy). And reading the new meta post, I realised that RC left under some unsavory circumstances. I just wanted to know what.

@Srivatsan I have no idea why Robin left.

@robjohn I guessed so (after all, you are here only for six months), which is why I asked Brian. :=)

@Srivatsan Robin was here 13 days ago.

@robjohn I see. He is then an occasional visitor. I don't remember reading any of his answers though.

Let me take an informal poll here. My impression is that threads with rude commenters and unsavory business etc. tend to work themselves out or simply blow over without closure anyway before mods ever show up. Does my impression align with others' here?

@Srivatsan I don’t think that the difference between seven months and six matters in this case.

@BrianMScott Hm, more gossip time? :)

Except that I don’t think that I even looked at meta until a few days ago, and I’ve not been here in chat much longer.

@anon I think it depends on the particular users involved. Most people would give up much before. For instance, I will just ignore the comment, apologise to the person or end the conversation saying that I am not interested.

@anon usually one side or the other loses interest if they don't work things out. Mods rarely need to intercede.

I guess that you are saying that when it does blow over, the mods show up only after all the damage is done. I think that is fair enough on their part, since I don't want them to keep interfering with every activity on the site. It's better for them as well as for us.

BD could have gone a long towards defusing the situation by explaining clearly exactly how he thought Paul’s answer was defective.

(ADULT TALK!) Join with Caution!!! (Goes to answer a question on the main site)

@BrianMScott Don't get me wrong, both sides were out of control in that volley. As was mentioned, the last serve was deleted. I never saw it, so I have no idea which straw broke the camel's back.

@robjohn I don’t actually agree. I sympathize with Paul. However, I don’t think that I’d call Bill’s remaining comments out of control, either.

@BrianMScott Hm, I find that frustrating, yes.

If I am told I am wrong or that the proof is circular etc., it would be nice to at least be pointed out where the mistake lies.

@BrianMScott I guess it is a subjective call. I tend to be rather moderate even on usenet, so the comments looked a bit much to me.

I’m pretty moderate by Usenet standards ...

Is Usenet as interesting as you people make it out to be? =)

@Srivatsan I agree. Bill told Paul to look at his answer, but that doesn't explain what is wrong with Paul's. (not to mention that you have to really think to understand Bill's answer; which letter represents 2, etc).

@robjohn It took me several readings of a single line of the answer before I got it. ("Hence, by induction, ..." =))

@Srivatsan It has a lot more flames and very colorful cranks.

@Srivatsan It used to be. Now it’s largely dead, a mixture of die-hards like me and utter loons $-$ and these loons aren’t nearly so interesting as some of the classic ones.

@BrianMScott I haven't been on sci.math since I started here, so I am sure it has changed a lot.

‘I would be interested in results for specific small cases as well as in the following question: For fixed n, does there exist m so that C come from any "reasonable" isotopy class? (Define reasonable reasonably.)’ -- math.stackexchange.com/questions/101797/…

@robjohn I have a sneaky suspicion you could be one of those classic loons. =)

@robjohn I left sci.math years ago in favor of alt.algebra.help and alt.math.undergrad. I got tired of the diagonal argument nonsense and the $0.999...\ne 1$ nonsense.

(just kidding, of course, Rob.)

Oh, I also still read de.sci.mathematik occasionally.

@BrianMScott At least in MSE, we get to hear newer nonsense like $0.99999\ldots 99998$. =)

@Srivatsan :-)

Anybody remember this guy coming to MSE? (I've been through dozens of 1\ne0.999 and Monty Hall revision nonsense over at 4chan. The funnest part is picking out the deliberate trolls from the legitimately confused.)

@anon "Philosopher, Mathematician, Software Developer, Educator" -- The expanse of his expertise is breath-taking indeed.

@Srivatsan I guess I could claim something of all 4, I taught math at UCLA for 2 years, I have been developing software for 23 years, I work for the Philosophy Dept at UCLA...

@robjohn Oh, you do (work for the Philosophy Dept. at UCLA)? Interesting.

The arrogance of ignorance.

Confusion, grandiosity, and limited awareness.

@Srivatsan Yes, the software I am writing is for teaching Logic, which is taught in the Philosophy Department in most schools.

@anon well, I could claim confusion and limited awareness :-)

Can you reveal anything about the software, or no?

Disclaimer: Mathematics stands on the foundation of truth and not on $|$bull shit$|$ that so called reformulators write!

Hey now. Sometimes mathematicians get things wrong, and it stays as dogma for days or centuries.

@KannappanSampath To play the devil's advocate, there is no foundation of truth in mathematics.

@Srivatsan I have done so a couple of times here. But in a nutshell, it supplies problems and grades them, it is used to give and grade tests. It has 6 modules: Derivations, Invalidities, Parsing, Rule Recognition, Symbolization, and Truth Tables.

It is used at UCLA and about a dozen institutions in the US, Canada, and Japan.

@robjohn Who is your customer really? I mean, is the entire department buying your s.w.? Or some faculty member?

What do parsing and rule recognition refer to? And I assume symbolization refers to putting an English description into predicate calculus or some such - is that correct?

@Srivatsan whoever teaches the first and second term logic courses.

As you can probably tell from my question, I don't know anything about how it works.. :)

@anon yes (for the symbolization), rule recognition supplies a logical deduction and the user is supposed to identify the rule used, or if it is a bogus deduction

Okay. Then parsing would probably be the reverse of symbolization.

@anon oh, I forgot about that; parsing is breaking a symbolic expression at the main connectives, yielding a logical tree

Those two modules cover the most elementary tasks :-)

The other modules cover more meaty ideas.

Alrighty. Didn't know these things had such fancy names. :)

@robjohn Taking them apars, so to speak.

@BrianMScott yes. The only module that deals with English statements is the Symbolization

In invalidity, you build models of finite universes that show a statement is not valid

@robjohn A statement is invalid or a deduction is invalid?

I mean: if a statement is invalid in a particular model, we can certainly conclude it is not a theorem. Is that what you meant, or something else?

@Srivatsan An argument, which could consist of a single expression, can be valid or invalid.

An derivation is marked as either correct or incorrect for the student.

Derivation being correct or incorrect makes sense. If its incorrect, the student should produce a model to back their claim (of invalidity), is it?

@Srivatsan No they are expected to produce correct derivations in that module. They are supposed to produce models in the Invalidity module.

If a derivation is deemed incorrect, they need to try again :-)

Oh, I was thinking we were discussing the invalidity module. =) But nevermind, I think I got it...

@robjohn How complicated are these logic systems? Any estimates on the #axioms, length of a proof, size of a model, and so on?

In the invalidity module, you are given an argument that is (hopefully) false and you are supposed to create a model which proves that.

Because obviously, these things would tend to blow up exponentially (in the worst case, but still)..

the models usually don't require more than 3 or 4 objects, but the proofs are as long or short as the student can make them

There are a handful of basic rules (axioms) and hundreds of derived rules and theorems in the program.

Plus you can prove your own theorems and use them

@robjohn "I want a proof that is at least 3 pages long." :D

@robjohn Ah, I see.

Will they also see statements independent of the axioms?

I have seen many analysis proofs consisting of more than 20 pages :-).

@JonasTeuwen Well, I was implying that short proofs will be rejected for being -ahem- too short.

Oh.

@Srivatsan Yes, and as they prove more of the derived rules, they can use them too.

@robjohn Ah, seems interesting. Hands on way to learn these logic concepts.

I’ll be damned if I can figure out sometimes what makes an answer popular. I just hit 110 on Are half of all numbers odd?, which I thought was a bit of a throwaway.

@Srivatsan Yes, and since they get immediate feedback on whether their answer is correct, they don't go until the next discussion section thinking that the wrong thing is right.

@BrianMScott with a +1 from you become still richer!

They can more confidently move on to the next topic.

@BrianMScott 110 points? I was puzzled that you meant so many votes. =)

@KannappanSampath Gracias, señor!

@Srivatsan Now that would call for a platinum badge with iridium pendants.

@robjohn Hm, reminds me of a project that we did. We had to assemble some electronic thing painfully from ground up, and we got no feedback whether things are going well or not until after about half the project is done. No points for guessing what happened then... ;)

Does this not represent insufficiency of info?

@BrianMScott I didn't know iridium was a precious metal. I thought it was more like, well, aluminium. =)

@Srivatsan You must recall that aluminium was ubiquitous those days.

Ubiquitous, maybe, I don't know. But was it precious? I guess so, actually.

Yes it was!

is anyone going thru the link I just put in?

@KannappanSampath That problem is workable. The standard error for 900 tosses of a fair coin is 15, so 490 heads is 2-2/3 standard errors $-$ rather a lot.

@KannappanSampath Yes. The p-value or whatever is missing. Many people assume a default value of (I'm not sure about the exact value) 5% as ok.

yes, p=1/20 is the default

@Srivatsan Even I thought so! Brian's answer came as a surprise!

@KannappanSampath I don't know what the p-value here is. Worse yet, I don't think I know what a p-value is. So.. =)

I don’t like the use of a default: in my opinion one should simply report the $p$-value and let the reader decide whether it’s significant in the given context. But it’s certainly true that $p=0.05$ is a commonly understood level of significance.

This means that with probability about 1-1/e we should expect 1 out of every 20 scientific papers just barely achieving p-value results of being false positives. Of course the public believes everything that looks better than chance in any scientific paper whatsoever means it's been established. (Except when it is contrary to their preconceptions, in which case they will rationalize that the scientific community has serious issues etc.)

I suppose we are ignoring those scientists who adjust values to get the right conclusion.

In this case the probability of getting that many or more heads in 900 tosses is about 0.0038. Double that for the prob. of being at least 40 heads away from 450 on either side.

@BrianMScott = very low. So your prediction based on the variance is quite right.

@Srivatsan And this is significant even at the 1% level, even for a two-sided test, so it’s pretty strong evidence.

Is it good to start retagging a few now? @Srivatsan @BrianMScott

By the way, Brian: the answer is nicely written; it deserves all the votes it got so far and more. Now, if and when it gets 110 votes, I will reconsider this judgement. =)

@KannappanSampath Sure. I am not sure Brian is into this retag business.

Actually, if you doing it now, I will do this later.

@Srivatsan I usually forget to check the tags even when I’m editing a question, though I’ve changed a few.

Actually, I think there's some 26-variable polynomial that generates primes at positive integer values.

Which answer are we talking about? 8-).

@anon I thought it's more like: whenever the polynomial assumes nonnegative integer values, it is a prime. Or so I remember; could be wrong..

@JonasTeuwen This one.

@anon I am not sure!

Oh yeah, that's probably it Sri.

Can you tell us what that holy polynomial is?

I believe that Srivatsan’s memory is correct, though I believe that it always assumes integer values.

Excellent.

@BrianMScott Yes, it is an integer polynomial.

@Kannappan: See here for one such holy polynomial. ;)

I think that one was written up in the Monthly quite a few years ago.

Wait, nevermind. Positive outputs and nonnegative arguments.

Holy Cr..., I don't see any utility for it!

I’ll probably be back later, but I’m off to do some much-needed grocery shopping.

I need to do some much-needed sleeping :-).

I think that there is an even more awesome polynomial which ZFC proves has a root if and only if ZFC is inconsistent.

:o

mathoverflow.net/questions/32892/…

Either way, I'm going to sleep now. Ciao.

Ciao. Me too.