The h Bar

I know a professor at Tata Institute of Fundamental Research.

R. Vijay.

user116211

@DanielSank this is for post graduates and phd applicants; not for undergrads.

user228700

Oh, cool :) TIFR is for postgraduates so :P

I see.

I wanted to say, Indian culture is wonderful.

I admire it very much in several ways.

user228700

8:01 AM

@DanielSank I see :) You should visit India sometime to know exactly how weird and wonderful it is :P

@KaumudiHarikumar I would like to do that.

user228700

:) Again, thanks so so much sir. I'll probably never forget this discussion I had :P

I appreciate vegetarian food very much and I admire that India produces such delicious vegetarian foods.

I also admire the way that so many Indians I have met have such a positive inclination toward life.

user116211

@DanielSank Your recipes!! The chilli one!!

@KaumudiHarikumar I did warn you :-)

8:03 AM

@MAFIA36790 Shall I link it here again? ;)

user116211

@KaumudiHarikumar You can bookmark that.

user228700

How to?

user228700

@JohnRennie And yes, you had :D

user116211

@DanielSank You had given me the link then; also the AMA post of yours contains that, if I remember ;)

@KaumudiHarikumar Before you go, let me say one last thing.

user116211

8:04 AM

@KaumudiHarikumar Go to transcripts

user228700

Yes? :)

user228700

@MAFIA36790 Okay..?

We discussed what I consider to be one of the two major concepts in statistical mechanics: we understand what macroscopic and microscopic variables mean, and therefore what the second law means.

user228700

Okay..?

user116211

@KaumudiHarikumar Then use bookmark a conversation on the right side.

Q: Is it possible way to discover the unkowns?

8:05 AM

The other important concept (in my opinion) is the idea that if you try to find the macroscopic state of maximum entropy under the condition of constraints, such a fixed amount of energy, then you naturally discover quantities such as temperature, pressure, and chemical potential.

user116211

0

here is a idea , as man we discovered many laws, formulas, event , ... in our surrounding environment, now if we simulate a virtual world with our knowledge in computer we expect it to work , because we guess that we know all of it, if a bug occur in simulation or something act different as we ex...

These things are Lagrange multipliers.

user116211

What's that?

user116211

I never get idea of such posts.

user228700

@DanielSank Ohh...okay.

8:06 AM

I wrote about this idea in a Physics Stack Exchange post. If you learn about Lagrange multipliers, then that post might be helpful.

user228700

I'll definitely learn about that in college so I will come back and check it out :)

Here's the chili recipe in case anyone wants it.

user116211

@KaumudiHarikumar There is a nice discussion about it in The Variational Principles of Mechanics by Lanczos.

@MAFIA36790 Oh, cool!

user228700

Also! Can you link to your blog again?

user228700

8:07 AM

I lost it :P

Sure.

user116211

yeh @daniel, do you have a blog?

Here is my totally uninteresting blog which has no actual posts yet

user116211

@DanielSank ahh!

user228700

@DanielSank I'll read them when you do post something :)

8:08 AM

I have three drafts written so far. I'm not sure when any of them will appear online. I make no promises ;)

user228700

Not sure if I'll understand anything, but will definitely try.

@MAFIA36790 It's poorly phrased, but basically it's asking if we can use a simulation to test if our theory is complete. And of course we can, though there are often easier ways to compare theory and experiment.

user116211

@DanielSank That book is quite good; maybe better than Goldstein; but it is hardly followed in any university course.

user228700

@DanielSank Okay, then! Again, I'd like to make and give you a medal or something for taking sooo much time and explaining this to me.

user228700

And also @JohnRennie

user116211

8:10 AM

@KaumudiHarikumar He always does that; he helped me many times earlier.

user228700

@MAFIA36790 I see :)

user228700

Now I'll have my lunch, come back and read all this one more time and carry on with the studying :P

@KaumudiHarikumar It was my pleasure. Actually, it was constructive for me too because I have not explained this topic before and I wanted to practice.

user228700

@DanielSank I see :) Okay, I hope to catch you another time! (But I live in India and you on the other side of the world so I'm not sure how likely that is :P) Bubye!

@KaumudiHarikumar bye :)

@MAFIA36790 when did I help you?

user116211

8:13 AM

@KaumudiHarikumar You can check the time-line when he is available.

I don't remember really ever having a long conversation with you before, but my memory is terrible.

user116211

@DanielSank oh man! I have to dig to get those; but you helped me understanding the derivation of Maxwell distribution function; prescribed me Reif and lot more.

@MAFIA36790 Wait, really!

That's hilarious because I was trying to re-derive it the other day and I got stuck.

Hahahaha

That's ironic!

user116211

@DanielSank Ohh ;P

What did you think of Reif?

Hmmm I should go to sleep.

user116211

8:17 AM

@DanielSank think of Reif? This is the saviour!! I was really having some hard time understanding fluctuations even in equilibrium; and he exactly discusses the point explicitly in the first chapter!!

@MAFIA36790 Yes! Isn't the first chapter a work of genius?

Without making a big deal, the first chapter teaches you all of the main ideas of statistical physics.

user116211

The book is really intuitive with lots of examples like explaining ensembles with coins.

user116211

@DanielSank indeed.

@MAFIA36790 Yes yes!

I'm so glad you liked the book.

user116211

@DanielSank That is one of the greatest helps when you prescribed it to me.

8:19 AM

@MAFIA36790 Oh very good then.

user116211

@DanielSank ;)

user116211

Btw, @DanielSank, do you have any idea of our next AMA session? Martin seems to be good enough to be the next guest? Well, I don't know about that.

user116211

I wanted Valter always to be the guest; but he seems to be not acquainted with the chat....

user116211

@DanielSank good night.

@MAFIA36790 I haven't talked to anyone about the AMA for a while.

@vzn has been the ring leader.

user116211

8:23 AM

@DanielSank ah! okay.

user116211

What about @johnR? He is always available ;))

@MAFIA36790 I'd love that.

@JohnRennie I want to ask you anything.

user116211

@JohnRennie ^^^

...but in a pseudo-official capacity.

We can wear fancy hats.

The problem is that I don't think my knowledge is in any way unusual.

8:25 AM

@JohnRennie bollocks

(did I use it right?)

What's the British equivalent of "bull---t"?

user116211

Also, we should celebrate when @JohnRennie reaches 200k!!

I know the same bits and pieces of physics that we all know. Where I think I score is that I'm good at explaining things.

user116211

Like those posts at meta MSE? i very much like the idea ;)

@JohnRennie Indeed.

The only specialist knowledge I have is of colloid science, but that's 20 years out of date now and I'm not sure it' that interesting anyway.

8:26 AM

Right now I need you to explain to me how to swear in British.

@JohnRennie Oh give up the modesty nonsense. People want to ask you stuff. Who says it will be about physics?

user116211

@JohnRennie Why not discuss it? Even Secret discussed his projects.

For example, I want to ask what's the best breakfast you've ever had.

Do not answer now

user116211

@DanielSank yeh, yeh ;))

I think bollocks is pretty universal. In French it's les valseuse I think. But it's used in much the same way.

@JohnRennie So I can say bollocks for "damn" and "bull---t"?

A truly versatile word!

Oh hey @MAFIA36790 are you from (in?) India?

8:28 AM

@DanielSank Yes, it can mean rubbish as in you're talking rubbish.

@JohnRennie got it.

user116211

@DanielSank oh yeah!

And it's also a generalised expression of dismay like damn and blast :-)

@MAFIA36790 Ok. So... I have a bit of a habit of studying swears and curses in foreign languages.

I know something about Russian, Spanish, and Dutch.

My father spent the second world war in the Punjab, and he learned an impressive array of urdu swearwords.

8:30 AM

At one point, I searched for the best swears and curses of each language.

user116211

@DanielSank Don't ask me about that then ;)

user116211

@JohnRennie WoWWW!!!!

@MAFIA36790 Well, what I was going to say, in all of my research, the most vile swear I found was actually in Hindi.

user116211

@DanielSank I'm not an expert, sorry ;P

There's one that literally means child of an owl, but I think actually means son of a wh###

8:31 AM

I will not repeat it here. I just thought it was amazing that such a phrase could come from a language spoken by what I think of as such a well-tempered people.

Russian has the best system of swearing, in my opinion, but not the best individual words.

user116211

@JohnRennie Your father must be veteran then ;)

@MAFIA36790 sadly he's no longer with us. But then he'd be over 100 by now.

user116211

@JohnRennie oh, sorry for that.

It happens to everyone. The only way to avoid having your parents die is to die before them, and that's not so great a strategy.

@JohnRennie Well said.

As I excuse myself to retire for the night, I reiterate my desire to have a chance to ask John Rennie anything.

Good night, all.

user116211

8:39 AM

@DanielSank o/

user116211

Even the God is not a commie; he gives someone 100yrs of life while some others less than 50.... what an inequality!!

8:51 AM

@MAFIA36790 o/

user116211

@yuggib hey.

What is that you don't understand in Bourbaki?

user116211

@yuggib The purpose of criteria of substitutions.

Q: Trying to understand the reasons for establishing the 'criteria of substitution'.

It is a way of formalizing the way we make proofs

If I recall correctly

user116211

What dis he mean when he wrote:

user116211

8:54 AM

> [...] even with the use of abbreviating symbols, the development of mathematics strictly in accordance with this principle would lead to extremely long chains of reasoning

user116211

long chains of reasoning?

user116211

I asked it at Math SE....

user116211

1

In Theory of Sets by N. Bourbaki, the author discusses some criteria named Criteria of Substitution while writing the reason for establishing that in the following excerpt: Formal mathematics contains only explicitly written assemblies. Nevertheless, even with the use of abbreviating symbol...

logic

user116211

Also, he did mention:

user116211

> These criteria are therefore not indispensable to the theory...

user116211

8:56 AM

That's what I couldn't conceive what he meant by that.

In principle you can derive every statement from the axioms, combining them using the inference rules

However at times it is useful to apply other criteria that help you shortening a proof

user116211

@yuggib ohh.

user116211

@yuggib Could you give an example?

Nevertheless, completely formal proofs would be so long that you never use them

@MAFIA36790 the principle of induction for natural numbers is true in ZFC

Therefore you can use it to prove theorems of ZFC

Without deriving them directly from the axioms

But appealing to induction

This is allowed because induction is true, and therefore can be used in a true inference

Criteria of substitution are similar in spirit (again if I recall correctly)

user116211

@yuggib okay.... then I need some time to study that!

user116211

9:02 AM

Bourbaki could have provided some illustrations but thanks @yuggib.