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Firstly, I was snarking.

Secondly, I think education should be valuer for its own sake rather than for its practical purposes. Realising one can do maths for maths's sake ought to be part of the syllabus ; one of the pitfalls of maths, and especially of maths for practical purposes, is that of mistaking them for a set of problem-solving techniques, which make understanding maths (and actual further problem solving) harder.

If up to 15 you only teach the maths that are practically useful, not looking into tome abstract details, it actually becomes very hard to do further maths, and since those one has learned are only a disjointed set of algorithms and quick answers, they are fast forgotten, too.

Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.

by linca (antonin POINT lucas AROBASE gmail.com) on Mon Nov 12th, 2007 at 08:56:01 AM EST
[ Parent ]
Could you give an example?  And....is it a visual experience, or is there some non-visual "place" where one revels in the pleasure of....maths....

(I mean, I an almost see it, I think, but I'm one of those who sees the application, I'm seeing it backwards maybe, from the machine to the parts to the materials to geology, into the atoms, and...out there in the land of the abstract....mathematics!

I almost called this diary "The Joy of Maths"...I keep thinking of applications...."What the numbers meant to Ka Ne Suss was that the thing was about to blow."

I'm intrigued!

Don't fight forces, use them R. Buckminster Fuller.

by rg (leopold dot lepster at google mail dot com) on Mon Nov 12th, 2007 at 07:52:23 PM EST
[ Parent ]
When one advances enough, the pleasures of maths become non-visual ; Maths after all is the art of abstract symbol manipulation. Finding a pathway between statement A - hypotheses, to statement B - consequences, logically true step by logically true step. Yet at the same time the steps are not trivial ; there is the joy of the treasure hunt. Maths isn't about numbers, indeed very often it is numbers, and annoying computations, that may make maths boring...

As an example, that first of all demonstrations, that of Pythagorean theorem : how does the figure prove that in a triangle with a 90° angle, a²+b²=n² ?


Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.

by linca (antonin POINT lucas AROBASE gmail.com) on Mon Nov 12th, 2007 at 08:26:32 PM EST
[ Parent ]
is this homework?

Life should consist in at least fifty percent pure waste of time, and the rest doing what you please.
by ceebs (bunchofwankers (at) gmail (dot) com) on Mon Nov 12th, 2007 at 08:36:48 PM EST
[ Parent ]
Yes.

Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.
by linca (antonin POINT lucas AROBASE gmail.com) on Mon Nov 12th, 2007 at 08:58:11 PM EST
[ Parent ]
(a+b)*(a+b)-n2=4(a*b)/2 (from the diagram)

a2+b2+2ab=2ab+n2

so a2+b2=n2

Life should consist in at least fifty percent pure waste of time, and the rest doing what you please.

by ceebs (bunchofwankers (at) gmail (dot) com) on Tue Nov 13th, 2007 at 07:48:34 AM EST
[ Parent ]
Yeah, this is a nice proof. But somehow it makes me feel like cheating, because it is only simple if you use a level of symbolic algebra that didn't exist in the old Greek days.
A slight variant on it, which is much nicer in my opinion, can be found here: proof #9 on
http://www.cut-the-knot.org/pythagoras/index.shtml
by GreatZamfir on Tue Nov 13th, 2007 at 08:01:19 AM EST
[ Parent ]
It did exist in the old greek days because they stated Pythagoras' theorem in terms of areas of squares built on sides, and addition of areas was a common technique.

At no point in the proof there is a nonhomogenoeous polynomial adding a length to an area, for instance. So Ceebs' argument can be written out in words involving areas.

I think that diagrammatic proof of Pythagoras' theorem may have originated in India?

We have met the enemy, and he is us — Pogo

by Migeru (migeru at eurotrib dot com) on Tue Nov 13th, 2007 at 08:10:50 AM EST
[ Parent ]
C'mon, it's not hard at all. It consists of producing a second graph from the above.

*Traitor*, n.
A benighted individual who perceives an illusory distinction between serving his nation and abetting the criminals who govern it.
by DoDo on Tue Nov 13th, 2007 at 06:38:59 AM EST
[ Parent ]
Woah!  Nothing is hard if you know how to do it.

I'm still pondering the idea of an "imageless" maths that invokes images (the diagram above), or a graph--something visual at any rate that stands for...the invisible maths behind the image...

So it may be easy, but easy is good (for me) if it helps me concentrate on the underlying aspect, in this case:

When one advances enough, the pleasures of maths become non-visual ; Maths after all is the art of abstract symbol manipulation.

(Thing is, I have pondered this and I am wondering whether maths' claim to be somehow bigger than the universe (maths gives us "the universe" + 1)--I mean the idea that maths "encompasses" the universe as compared to the universe being "bigger than maths"--Heh, I'll have to try and explain this again later, but I mean something like: "What does it mean that we can't beyond a certain exponential--I was thinking about mathematical models of the universe--there is the "empty box" model, we are in it and the sides are an endless distance away.  Then there is the "closed form" model, balls, saddles, but always (inevitably) seen from "outside"...heh...I'll post this just to remind myself that I had a thought in there somewhere.

Don't fight forces, use them R. Buckminster Fuller.

by rg (leopold dot lepster at google mail dot com) on Tue Nov 13th, 2007 at 07:40:16 AM EST
[ Parent ]
See the book proofs without words.

Notice that before the development of symbolic algebra in the middle ages, elgebra had always a geometric interpretation. Squares were the areas of squares. Linear quantities were the lengths of segments. Cubes were the volumes of actual cubes. Inhomogeneous polynomials (mixing quantities of different degree) didn't often occur.

Mathematics has always been visual, touchy-feely, intuitive, until the formalization in the 19th century.

We have met the enemy, and he is us — Pogo

by Migeru (migeru at eurotrib dot com) on Tue Nov 13th, 2007 at 08:16:03 AM EST
[ Parent ]
Woah!  Nothing is hard if you know how to do it.

But this one should be really easy. We had to find this out on ourselves, I don't know, maybe as sixth graders.

I mean the idea that maths "encompasses" the universe as compared to the universe being "bigger than maths"

Do you know that Set Theory proves that there is no Universe?

Then there is the "closed form" model, balls, saddles

Saddles are a representation of open ever-expanding hyperbolic universes.

*Traitor*, n.
A benighted individual who perceives an illusory distinction between serving his nation and abetting the criminals who govern it.

by DoDo on Tue Nov 13th, 2007 at 08:40:52 AM EST
[ Parent ]
Mathematical education in the communist countries was notably more advanced than anywhere else. Stuff was learned about two to three years earlier in Russia or Yougoslavia than in France, for example.

Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.
by linca (antonin POINT lucas AROBASE gmail.com) on Tue Nov 13th, 2007 at 08:49:22 AM EST
[ Parent ]
I know it's about 26 years since i had to do anything like that. It's good to see that I still have the tools in my mental toolbox, (albeit a little dusty, plus there are probably newer shinyer mental tools out there somewhere which I havent aquired)

Life should consist in at least fifty percent pure waste of time, and the rest doing what you please.
by ceebs (bunchofwankers (at) gmail (dot) com) on Tue Nov 13th, 2007 at 07:53:07 AM EST
[ Parent ]
When one advances enough, the pleasures of maths become non-visual ; Maths after all is the art of abstract symbol manipulation.

What? Nonsense: that's logic you're thinking of. Abstract symbol manipulation is a tool, most of the time, not an end.
by Colman (colman at eurotrib.com) on Tue Nov 13th, 2007 at 07:43:53 AM EST
[ Parent ]
Which parts of maths deal with stuff that are not abstract symbols ?

Logic is how you are allowed to manipulate abstract symbols ; the rest of maths is deciding about some abstract symbol, and then playing with them a lot...

Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.

by linca (antonin POINT lucas AROBASE gmail.com) on Tue Nov 13th, 2007 at 08:13:44 AM EST
[ Parent ]
Almost all of it. Which parts of mathematics deal solely with abstract symbols? Which value of "abstract" are you using?
by Colman (colman at eurotrib.com) on Tue Nov 13th, 2007 at 08:21:28 AM EST
[ Parent ]
Which part of mathematics don't deal with abstract symbols, i.e. with arbitrarily chosen words or signs that point not to a "real" entity from the concrete world, but to a thought entity that behaves according to some abstract hypotheses ?

Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.
by linca (antonin POINT lucas AROBASE gmail.com) on Tue Nov 13th, 2007 at 08:28:40 AM EST
[ Parent ]
I do a fair bit of category theory: I think that the set of natural numbers is a concrete example. To my way of thinking, in the context of mathematics, an abstract symbol is one that doesn't have any meaning behind it.
by Colman (colman at eurotrib.com) on Tue Nov 13th, 2007 at 08:31:54 AM EST
[ Parent ]
What do you mean? The free monoidal category on one object is indexed by the natural numbers.

We have met the enemy, and he is us — Pogo
by Migeru (migeru at eurotrib dot com) on Tue Nov 13th, 2007 at 08:41:06 AM EST
[ Parent ]
Yes, and that's a concrete example as well.
by Colman (colman at eurotrib.com) on Tue Nov 13th, 2007 at 09:12:29 AM EST
[ Parent ]
I don't really see how N is concrete, i.e. how it has an existence in the real world.

In my view N only has the meaning we give it through axioms ; axioms which are rules on how to write proofs.

What do you mean by 'meaning' ? :)

Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.

by linca (antonin POINT lucas AROBASE gmail.com) on Tue Nov 13th, 2007 at 08:45:32 AM EST
[ Parent ]
The natural numbers predate the Peano axioms bu how many millennia exactly?

Axiomatization is not the prerequisite for mathematics, it's the endpoint.

We have met the enemy, and he is us — Pogo

by Migeru (migeru at eurotrib dot com) on Tue Nov 13th, 2007 at 09:08:19 AM EST
[ Parent ]
Euclid did have an axiomatisation of natural numbers... We switched axioms more recently, but axiomatisation is as old as mathematics.

Also, is R more concrete than the set of p-adic numbers? is Euclidean geometry less abstract than other geometries ?

Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.

by linca (antonin POINT lucas AROBASE gmail.com) on Tue Nov 13th, 2007 at 09:22:13 AM EST
[ Parent ]
Actually, spherical geometry is more concrete than Euclidean geometry because it is the geometry of the visual field.

R is more concrete than the set of p-adic numbers. That is why it was invented centuries earlier.

And while Euclid and his contemporaries had axioms, mathematics had existed before them. The greeks may have invented the axiomatic-deductive method, but they did not invent mathematics.

We have met the enemy, and he is us — Pogo

by Migeru (migeru at eurotrib dot com) on Tue Nov 13th, 2007 at 09:40:25 AM EST
[ Parent ]
Then why was Euclidean geometry invented a long time before spherical geometry ?

Which geometry is concrete to a blind person ?*

It seems you define concrete as intuitively accessible to the human brain... It makes god a very concrete concept nowadays.

Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.

by linca (antonin POINT lucas AROBASE gmail.com) on Tue Nov 13th, 2007 at 09:45:31 AM EST
[ Parent ]
It seems you define concrete as intuitively accessible to the human brain...
Where else does human mathematics come from?

As for spherical geometry being invented after euclidean geometry, I don't know what came first, but spherical geometry was highly developed by babylonian astronomers while the Babylonian value for pi was still the integer 3.

We have met the enemy, and he is us — Pogo

by Migeru (migeru at eurotrib dot com) on Tue Nov 13th, 2007 at 09:55:12 AM EST
[ Parent ]
Is mathematics dependent on society ? We were wondering elsewhere on the relative intuitiveness of fractions and decimals. If concreteness is linked to intuitive understandability and conceivability, depending on whether a society insists on decimals or fractions one concept or the other becomes more concrete. Concreteness  isn't constant across human brains, according to your definition...

Also, is there mathematical truth independent of thought processes : is logic only a cognitive process ? Colman was contrasting logics with the rest of mathematics. Is logic "true" because it agrees with our thought processes - but many people think without adhering to the laws of logic. Why would logic be different from the rest of maths ?

Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.

by linca (antonin POINT lucas AROBASE gmail.com) on Tue Nov 13th, 2007 at 10:16:45 AM EST
[ Parent ]
What do you mean by 'real world'?

Concepts of abstract and concrete can depend where you're looking at them from: N can be relatively concrete. In a moment we can consider what is concrete, precisely.

by Colman (colman at eurotrib.com) on Tue Nov 13th, 2007 at 09:11:53 AM EST
[ Parent ]
Real maths - as opposed to mechanical arithmetic - is a complicated little beastie and varies from field to field.

You have a couple of things going on - your intuition about the structures you're dealing with, your visualisation of them (which I don't mean in a way that's easily mappable to visualising real things, but you're using the same part of the mind), the symbolic representations and the available facts about the symbolic representations. So you're working on several levels, and different people enjoy different parts. Generally I think people are guided by intuition to propose things which they then need the symbolic machinery to prove - it's too easy to let your imagination run away with you. Sometimes your intuition is mistaken and the symbolic machinery will help you understand why.

by Colman (colman at eurotrib.com) on Tue Nov 13th, 2007 at 07:56:03 AM EST
[ Parent ]

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