Wolfram Mathematica

12:03 AM

@Rojo not a good sign. I'm sure the last thing they want to happen is for a thriving black market to form.

@OleksandrR. They think they can force handle the market

I remember a couple of months ago, one of them said that "they had come to an agreement with the main exchange sites so that the "illegal" exchange rate would go down". Not in those words. Of course, he was just talking nonsense

Oleksandr R.

Managing expectations by giving false, misleading, or confusing statements seems to be a key tool among central bankers today. Greenspan was a master at that and Bernanke seems to be quite accomplished as well. I don't regard it as a good thing.

Fedspeak

{|class="toccolours" style="float: right; margin-left: 0.5em; margin-right: 1em; font-size: 85%; background:#c6dbf7; color:black; width:20em; max-width: 25%;" cellspacing="5" |style="text-align: left;"|Known as Fed Speak, the convoluted rhetoric has befuddled even the wisest of interpreters. |- |style="text-align: left;"|— Wealth Building Strategies in Energy, Metals and Other Markets |} In monetary policy of the United States, the term Fedspeak (also known as Greenspeak) is what Alan Blinder called "a turgid dialect of English" used by Federal Reserve Board chairmen in making intentionally...

R.M

Watch out folks, this might be the beginning of anonymous spam/vandalism mathematica.stackexchange.com/suggested-edits/345

Rojo

@R.M Grrr

Oleksandr R.

@R.M Uh oh. Well, am I glad you got your 20k so you can deal with this for us! :)

R.M

12:10 AM

Anyone with 5k should be able to see the suggested edit queue if I recall correctly, but thanks :)

does any bold person want to check out that link? :P

Probably it's just some random asdfgh smashings

Oleksandr R.

12:22 AM

@R.M yes, they don't seem to be real addresses. Perhaps testing the waters. I was a moderator on a discussion forum and we had real trouble with spam until eventually I changed it so that new members' posts had to be moderator-approved. The volume of submitted spam posts was still somewhat overwhelming though.

acl

but what's the motivation? testing to see if spam links can be inserted?

R.M

This is the internet. People don't need any motivation

acl

a good point, but, why not post insults if you're just going to vandalise things randomly?

Rojo

lmskdhfjlajhmlajcmlfaslvfajsdfa.com/alskdfjasldkj

acl

@Rojo jjjjjjjjjjjjjjjjjjjjjjjjjjjjj

jjj jjj jjjjjjj jjj?

still, easily dealt with,it seems

Rojo

12:31 AM

@acl Mmmpppmpm fppmfpmmmfmp'fmm fmpmfpmmmfmp fmmfmfpfmpfmppffmmmppmpm fmpppf ppmmppmmmppp?

namesuppressed.com/kenny

I could've used MMA but I'm eating cheese with one hand

That "but" made no sense

I need to go to the toilet but my ex is doing a final exam right now

That one either

acl

the second less than the first

Rojo

Yes

However, I feel there is some relationship between my delaying going to the toilet and the exam. Anyway, moving on

acl

@Rojo could be

the universe is ever mysterious

belisarius

12:56 AM

@acl Realizing how mysterious the universe is by not going to the toilet sounds like a drunkard's path to Zen

Rojo

I went already

Couldn't take it

acl

@belisarius a random walk eventually covers the plane, and clearly Zen lies on the plane. QED

belisarius

@acl The dimension of Zen is irrational, as any beginner can testify

Oleksandr R.

1:16 AM

@acl a surprising number of spammers are not bots, but actual people (being paid a pittance for a huge volume of spam). They may be checking to see how much effort they need to go to, to get a post full of nonsense published, with the intention of coming back later and upping their game--or, their efforts, thus compensation, might be measured by some rather stupid software that can't tell these from real spam links.

One of their favorite tactics, and one that works well, is copying questions from other forums with a similar subject. Fortunately I think our topic is narrow enough that this approach is unlikely to be feasible.

jmlopez

Hey guys, anyone knows an easy and intuitive way to make these figures? mathworld.wolfram.com/images/eps-gif/HopfAlgebra2_1000.gif

belisarius

@jmlopez File not found? wrong link?

Oleksandr R.

@jmlopez looks like a job for LevelScheme. I haven't used it, personally, but the general layout is perhaps not dissimilar from an energy level diagram.

jmlopez

@OleksandrR., has anyone ask this before? I've been looking for something like, function map figures, but I haven't found anything related

Looking here: mathworld.wolfram.com/HopfAlgebra.html makes me wonder how they made those pictures.

Is there a name for these type of figures?

Oleksandr R.

@jmlopez I really don't know. Making figures is far outside my usual domain; I usually avoid it as far as possible. All I know is LevelScheme is highly regarded and can make energy level diagrams amongst others. What these diagrams are called I don't know either: usually they are just referred to as "diagram"...

R.M

1:27 AM

@jmlopez you can do it with TikZ, for sure

Hold on, I remember a question that might be close enough...

You can do something like that using the graph objects... with the vertices being H\[CircleTimes]H, the edge labels being Δ, etc.

jmlopez

@R.M, yeah, that's what I have in mind

I can certainly do it but I was just wondering if anyone had made some sort of function to make it easier.

Or maybe find out if the person who wrote mathworld.wolfram.com/HopfAlgebra.html used Mathematica to make the figures.

R.M

probably not, unless they create these diagrams a lot in Mathematica... if I were writing a publication and needed to make something like this, I'd probably just use TikZ

jmlopez

I think I'll just stick to Mathematica for the moment. It shouldn't be too hard to make functions to tell it how to display a map from a set to another.

R.M

Anyway, this question was what I was thinking of... You just need to change the vertices, colour the edges, etc. which shouldn't be too hard. Also, that uses the older functions because Mr.W doesn't have v8. The newer graph objects might be more convenient.

A simpler approach using graphics primitives would actually be better I think.

You can use Jens' post on circuit drawing as a framework for creating the basic blocks that will lay out your set connections

jmlopez

2:00 AM

@R.M, thanks, the first question is exactly what I want. I like how the vertices can be moved in the second piece of code that Mr.W provided.

rcollyer

2:18 AM

@jmlopez It's called category theory, and those diagrams are the hall mark of it. But, that is as much as I know of it.

Category theory

Category theory is an area of study in mathematics that examines in an abstract way the properties of particular mathematical concepts, by formalising them as collections of objects and arrows (also called morphisms, although this term also has a specific, non category-theoretical meaning), where these collections satisfy some basic conditions. Many significant areas of mathematics can be formalised as categories, and the use of category theory allows many intricate and subtle mathematical results in these fields to be stated, and proved, in a much simpler way than without the use of cat...

belisarius

2:37 AM

@rcollyer That was Algebra 4xx when I was at uni

rcollyer

@belisarius we never touched upon categories, only groups and rings.

belisarius

@rcollyer Well, I didn't take that course either

rcollyer

@belisarius :)

I find I'm using a lot of group theory as it is very useful in quantum mechanics.

belisarius

@rcollyer Some friends said it was really interesting

Rojo

Math only messes your MMA

You end up taking the Trace of a matrix

or creating a Set[stuff, stuff2, stuff3]

rcollyer

2:48 AM

:)

Rojo

and then finding a Partition[Set[stuff, stuff2, stuff3]]

The Range[Sin[t]]

etc etc

belisarius

@rcollyer Most physical theories are based on some kind of symmetry, yes

rcollyer

@belisarius It is stuff that you'd be able to figure out on your own if you just thought about it for a bit. Obviously that only applies to the first couple of weeks, but that is a good enough hook.

@belisarius and all conservation laws.

Noether's theorem

Noether's (first) theorem states that any differentiable symmetry of the action of a physical system has a corresponding conservation law. The theorem was proved by German mathematician Emmy Noether in 1915 and published in 1918. The action of a physical system is the integral over time of a Lagrangian function (which may or may not be an integral over space of a Lagrangian density function), from which the system's behavior can be determined by the principle of least action. Noether's theorem has become a fundamental tool of modern theoretical physics and the calculus of variations. A g...

belisarius

@rcollyer Yep. That was Mech 101 :)

rcollyer

@belisarius we didn't get to that until 3rd year (or were supposed to at any rate).

Did they teach Lagrangian mechanics that early?

belisarius

2:51 AM

@rcollyer Yep Mech 101 was in third year :)

rcollyer

@belisarius Ah. I saw the 101 and assumed that it was a first year course.

belisarius

@rcollyer BTW Did you see the The Feynman Videos for Dummys on the MS site?

rcollyer

@belisarius you pointed me at them. I only looked at the one.

belisarius

He explains cons. laws for lawyers. Wonderful

rcollyer

That's sounds really funny.

belisarius

2:54 AM

@rcollyer RF was a funny and happy person, yes

rcollyer

@belisarius don't forget certifiably brilliant. Although, he always said his toolbox just contained a different set of tools.

belisarius

@rcollyer What I admire the most of him is the huge area of expertise.

rcollyer

@belisarius he never stopped playing with what he learned. Constantly pushed himself to go farther. A lot of times it was just to show off, the safe cracking, etc. But, other times, it was just to learn something new.

belisarius

@rcollyer He did brilliantly so many things that I could only be ashamed of my performance :)

from safe cracking, yes, to playing bongos

not to mention physics

rcollyer

belisarius

2:59 AM

Ha

nice!

He was also such a honest person!

rcollyer

I wish I could say I came up with it, but it was on a blog I read called Study Hacks which, among other things, advocates a different way of approaching careers and learning. Worth the read.

belisarius

@rcollyer Seems a nice site. Will take a look. Thanks!

rcollyer

@belisarius the author is somewhat of a heretic in his views. But, there is little denying his approach works: 2 or 3 books while working on his Ph.D.

belisarius

@rcollyer That depends on how long he took to get his PhD :)

rcollyer

@belisarius I think within a 6 - 7 year time frame, so normal.

belisarius

3:07 AM

@rcollyer Not bad for 3 books

rcollyer

@belisarius 4, the dissertation.

belisarius

Given that conditions, in your dissertation you stand up and say "I wrote 3 books already, Thanks"

need to leave