Showing posts with label mathematics in general. Show all posts
Showing posts with label mathematics in general. Show all posts

Wednesday, March 4, 2020

Love or Math


Re Drayton’s Endimion and Phoebe:

He would like to have depicted the Platonic ascent from carnal to intelligible love, but has really no idea of what one would find at the top of the ladder.  He has to fill up with astronomy and the theory of numbers.
-- C.S. Lewis, English Literature in the Sixteenth Century (1944), p. 532

Actually, not a bad expedient.

The idea is developed  here:


Note:  The title of this post alludes to Edward Frenkel’s book, Love and Math, considered here:


Wednesday, December 2, 2015

Mathematical Epigrams


Last Man Standing:  a firefight implementation of the Euclidean Algorithm.

The Gunslinger's Dilemma


~

Hotel California:  an ergodic set.

Checkout time:  Doomsday


~

A person wearing a T-shirt that says “I’m with Stupid” is termed co-stupid.
A co-stupid person who is himself stupid  is termed bi-stupid.



Example of a non-stupid module showing
Universal Co-Stupidity

Just as there is a universal element in the Category of Co-stupidity, so too the dual category of Bi-stupidity has a universal element;  his name is Donald Trump.

Note that this does not imply that Trump himself is maximally stupid, nor even that he is especially stupid at all.  All that is required is that he qualify (marginally) as stupid (which isn’t hard to do, since stupidity appears to be nearly universal these days, a fact not lost on the Republican Presidential candidates, who have learned specifically to target that demographic).  Indeed, as it happens, he seems to be cleverer than most.

Note:  The Boolean inverse of stupidity is smartness.  A detailed proposal for developing this  can be found here:
http://www.nytimes.com/2015/11/29/opinion/the-smartness-act-of-2015.html?_r=0


For more on the mathematical theory of stupidity, try this:

     De Stultitiâ

For the concept "pseudo-stupid", here:

     Difficulty is Hard.

For more on the pataphysical theory of categories, this:


.

Friday, June 12, 2015

The latest in Math Porn


An attempt at moyenne (ou basse) vulgarisation, by a (slumming) specialist in Category Theory:

To make mathematics palatable for the lay reader, the author must sweeten the pill. There are many ways to do this, but Eugenia Cheng is surely the first to have approached the task literally, writing a math book in which almost every chapter begins with a recipe for dessert.
Cheng never quite overeggs her metaphor of the mathematician as chef, however …
But while she successfully conveys a love of her subject, I felt shortchanged; Cheng never explains exactly how category theory has shaped math, never shares its major results and its great unsolved questions. Perhaps she thought the answers would be too arcane or complicated for a book aimed at general readers.
http://www.nytimes.com/2015/06/14/books/review/how-to-bake-pi-by-eugenia-cheng.html?emc=edit_bk_20150612&nl=books&nlid=5160164&_r=0

Hard to get more random than that.   How mathematics is like a poker game;  how mathematics is like baseball;  how mathematics is like a chimpanzee riding a bicycle …


It is not that one cannot introduce ideas of category theory to an intelligent general audience, without flattering their baser natures with similes from the kitchen. Lawvere & Schanuel do just that in Conceptual Mathematics (1997): elementary in the sense that it begins from the elements, without assuming technical prerequisites from special fields, but sophisticated in that it doesn’t glide or gloss over.  But you won't find that sort of thing reviewed in the New York Times, where (increasingly) puff-pastry drives out the protein.

Saturday, April 4, 2015

Taylor Swift nude pixxx!


Among the challenges for anyone attempting haute vulgarisation in the exact sciences, is the following phenomenon, epigrammatically summed-up by Stephen Hawking:

“Every equation  halves the number of readers.”

Now, blogspot.com helpfully supplies realtime stats;  so we shall test that proposition experimentally.

This post has been up for twenty minutes now, and … lessee … by the meter, it is presently enjoying roughly a million pageviews, based upon the subject-line alone.  (Were we to add an actual photograph, it would probably crash the server.)

Let us then add one equation, and re-sample:

2 + 2 = 4

[Update, twenty minutes later]  Well, even that proved too much for most:  viewership has plummeted by half.
(Rather a simple repellent, that;  like the storefronts that play classical music to shoo away the teenagers.)

Let’s try again, with something more substantial:


Einstein field equation


Whoa -- overkill!  That one knocked out all but a hardy hundred-thousand!

Okay, let’s dial it back:

Fresnel formula

Aww, c’mon, gang, that’s just trig!  But ninety-percent of Web-surfers to this page have just dropped out, leaving a bare thousand.
 
Probably just a statistical fluke.   Let’s try again:


Klein-Gordan

D-d-dang!  Hawking if anything put it too mildly.   Now there are only a sturdy hundred viewing this page.
 
Well, those formulae were all from physics (Hawking's field).   Let’s try again, with one from number-theory:


Riemann zeta function

Alright, end of experiment.   At this moment, there are only a bare ten readers viewing this page.

But these are the readers we want!

~




For many mathy goodies, click here:


[Update]  Advice to onanists:
Do not indulge that private vice.  It can lead to insanity, and it grows hair on your palms.

Monday, March 16, 2015

On “The Nature of Mathematical Knowledge” (enlarged)

That question is about as interesting as the nature of our knowledge of elephants.  We are interested in the zoology of elephants, not in the specificities of classroom biology lessons, or the economics of zoos.  We are uninterested in each blind man’s subjective and partial report upon the individual organs of these splendid creatures.

Mathematical knowledge, like pachydermal knowledge, is imperfect knowledge of something real that exists independently of us. By contrast, just which images we manage to form of these objects  are very much dependent upon ourselves – and to that extent, of interest only to unemployed social workers.


As our former math teacher put it:

Mathematics has a real content which transcends the inadequacies of our efforts to formalize it.
-- Andrew Gleason,  Fundamentals of Abstract Analysis (1966), p. v.

Or, from a philosopher:

For most mathematicians most of the time, having a feel for what is evident is important, but it is also enough: There is no further need for a theory of what that feel is.
-- Shaughan Lavine, Understanding the Infinite (1994)

*

Actually, it should not be deduced from the above, that I am somehow dissing our big friends the elephants.  A Theory of Elephants is considerably more promising than that idle grail of the physicists, a Theory of Everything.

The outstanding problem in the Theory of Elephants is the ontological status of BABAR – THE KING !!!!!

His Majesty ... The King !!!


An agnostic or non-Realist version, wilfully po-faced:

Our deductivist proposes clean answers to philosophical questions.  What is mathematics about?  Nothing … What is mathematical knowledge?  It is knowledge of what follows from what.  Mathematical knowledge is logical knowledge.
-- Stewart Shapiro, Thinking about Mathematics (2000), p. 150

*

*

There is a systematic ambiguity (roughly that of actio versus actum) to the term mathematics:

(I) The praxis of mathematizing.  This is a human pastime, comparable to needlework or basketball.
(II) The truths of mathematics.  Or, more or less synonymously: The real (though invisible) world.  These, in themselves, bear no dependency upon human practice or to any species whatever;  they existed before we were born.

The above may count as a polemical reformulation of roughly the dichotomy in the title of Hao Wang’s fine essay, “The Theory and Practice of Mathematics”.

*
In 1950, Raymond Wilder gave an address, “The Cultural Basis of Mathematics”, reprinted in  various places, and later wrote a whole book on the subject, Mathematics as a Cultural System (1981).   Bien-pensant commentors treat these with grave respect;  but the notion is practically nonsense.  For, if we take mathematics in sense (II) – the only sense of interest to us here – that is like saying “The cultural basis of elephants”:  there is none.  There is a cultural basis of circus stunts, of mouse- and peanut-myths, of Dumbo, but not of elephants themselves.  Their basis is their own four feet.

Why should the culture of mathematics  (necessarily, sensu I) – that is, the foibles of mathematicians – retain our attention?  The purely “human side” of mathematicians  is generally less interesting than that of country music stars.  A lot of mathematicians are pretty Asperger’s, frankly.
(For a poignant illustration of this, read The Genius in My Basement.)

There is, we grant, a certain interest in the sociology of mathematics, or in biographies of the great mathematicians. Intellectually, it is on a level with gossip about the off-court antics of basketball stars.  Fun, but of no mathematical (or basketball) interest.   It’s just a way for the mind to chew gum while it’s too exhausted to do anything substantial.  To get real, do math (or play basketball).

Not to come down too hard on the small geeky community that does follow the doings of math and physics whizzes; I number myself among them.   It would even be neat  if, instead of collecting baseball cards, people collected mathematician cards (“Trajea two Steven Smales for a John Milnor!”) .  -- By “people”, I here mean “eight-year olds”.

*

More interesting is the purported “reduction of mathematics to logic”.  It is not initially clear, however,  to what extent this program, if successful on its own terms, would enlighten us as to mathematics-sensu-(II), as opposed to the sense-(I) territory of our own mathematical formulations and formalizations (these being, after all, largely for mere convenience).  It might be more along the lines of the demonstration of the equivalence of the Heisenberg-style matrix-mechanics formulation with that of the Schroedinger-style wave formulation, of quantum mechanics. That feat didn't tell us all that much about the actual phenomena of physics,  apart from the fact that the world is a many-splendored thing, and can be described -- blind-man-fondling-elephant-fashion -- in a variety of ways.  It’s more like deciding whether today’s symposium shall be conducted in English or in French.


*

That said --
We argued here that the axiomatic method is cognitively post-hoc, and that  only in cases where (as with the Euclidean axioms) their positing is transparently motivated by our experience of the sensible world, is a top-down, axiomatic presentation  pedagogically sound.   Thus similarly in physics:

In lecture after lecture, and essay after essay,  Einstein began, not with an introduction to the subject at hand, but with an overview of how he’d arrived at that subject, or of how scientists in general  arrive at subjects in general. … For Einstein himself, the results of science had become incomprehensible without an understanding of the processes that led to them.
Richard Panek, The Invisible Century (2004), p. 153-4

C'est exact;  and the farther physics wanders from our human experience, and the father math develops beyond anything the world has seen before, the more necessary such a psycho-cognitive ladder does become.

*

Something like the dichotomy outlined above  must have been behind André Weil’s tart remark, in “History of Mathematics” (reprinted in Collected Works v. III as (1978b)):

Some universities have established chairs for “the history and philosophy of mathematics”;  it is hard for me to imagine  what those two have in common.

For:  the one is situated and contingent, the other timeless and beyond place.


*

Footnote:   These remarks about mathematics  apply  mutatis mutandis  to the Deity.  Deliberately confusing the distinction between truth and praxis, Karen Armstrong wrote a book -- a minor best-seller -- with the impudent title A History of God.  (At least she put A, not The; probably saved herself an extra millennium in Purgatory right there.)

*

Lakatos’ classic dialectical-dialogue Proofs and Refutations (you see the Hegel-style paradox already in the title), though focussing on the (as he persuasively argues, in the course of a detailed case-study spanning many decades) micro-level mess of actual mathematical progress, is yet Realist at its core:  the subtitle is “The Logic of Mathematical Discovery”, not “The Sociology of  ‘Mathematical’ Invention”.   We quoted him in another context  thus:

As far as naïve classification is concerned, nominalists are close to the truth when claiming that the only thing that polyhedra have in common  is their name.  But after a few centuries of proofs and refutations, as the theory of polyhedra develops, and theoretical classification replaces naïve classification,  the balance changes in favour of the realist.
-- Imre Lakatos, Proofs and Refutations (1976), p. 92

In an appendix to the main work, he offers a Hegelian formulation, one which (by the time the reader has progressed this far) has a certain paradoxical piquancy:

Mathematics, this product of human activity, ‘alienates itself’ [in the sense of Hegel and Marx] from the human activity, which has been producing it.  It becomes a living, growing organism, that acquires a certain autonomy [emphasis in original] from the activity that produced  it.  … The activity of human mathematicians, as it appears in history, is only a fumbling realisation of the wonderful dialectic of mathematical ideas.
-- Imre Lakatos, Proofs and Refutations (1976), p. 146

Plato, in his Paradise, smiles.

Saturday, March 14, 2015

Happy Pi Day !

As everybody knows, today is International Pi Day, celebrating that round-est of transcendental numbers.   Parades, be-ins, and village festivities  typically last far into the night.
This year's celebration is especially intense, since today is not only 3/14, but 3/14/15.
In honor of this joyful occasion, we post a banquet of appetizers  in the form of quotes from essays.  Click on the link for the full meal.


Traditional festivities for Pi Day
Note:  Next year,  on 3/14/16, we celebrate "Approximate Pi Day", since 3.14159  ≈  3.1416.   (That is, as the saying goes, "Good enough for government work";  all federal employees will have the day off.)  To anyone who objects that "That's just silly", reply:  On the contrary, it is considerably more rational.


~    ~    ~



“Gauss saw things in terms of sheets embedded in three-space, the natural abstraction from his experience as a land-surveyor.  Riemann shifted the view to that interior to the space.”

A near-synonym of the math-word deep, but shorn of all irrelevant aesthetic echo, is:  “highly nontrivial”.   The term is decidedly commendatory, though to a layman it might sound like faint praise.

But what then, of the java, that flows from the mug whose reality we have just proved???  Why, it flows to fuel the brains of mathematicians!
http://worldofdrjustice.blogspot.com/2014/12/a-new-proof-of-existence-of-coffee-cups.html


A classic joke runs: 

The Axiom of Choice is obviously true;  the Well-Ordering Principle, obviously false;  and Zorn’s Lemma -- who can understand it?
It would be worth your while to obtain a Ph.D. in mathematics, simply to be able to get that joke (which contains deep truths).   Nothing else in the universe is nearly so funny.
http://worldofdrjustice.blogspot.com/2011/12/minimum-axiomatization-for-reality-part.html

"Some it-from-bit proponents  stretch this logic still further.  They look on the universe as a giant computer simulation."

“I do not know whether it can deal with jelly-like or cloud-like entities, with mushy viscous messes  that do not break up into manifest units.  I suspect that nothing is beyond the technical ingenuity of men…” http://worldofdrjustice.blogspot.com/2012/04/ontology-of-logic-updated.html

I personally attended Professor Langlands IAS lecture series (autumn 1999);  in the first of these he stated that he'd wanted to be a physicist, but physics was "too difficult", so he had to settle for being a humble mathematics professor at the Institute for Advanced Studies.   Nor was this a pose;  his whole manner is that of straightforward humility, very … Canadian.
http://worldofdrjustice.blogspot.com/2014/03/on-brilliance-and-boredom.html

To vary Nestroy’s celebrated epigram -- “Bis die Topologie gehts noch, aber von da bis sheaf theory  zieht sich der Weg.”

We may define pure mathematics as the subject in which Bertrand Russell does not know what he is talking about, though what he says is none the less true.

A more adequate symbol would be simply a rectangle with opposite edges identified -- or better yet, the toroidal covering-space which carpets RR with infinite replications of this patch-sample.  (Already how distantly we have left behind the donut!)

Mathematicians, like philosophers, and unlike anyone else (including even lexicographers), are given to a certain semantic Akribie --  an extraordinary self-critical attention to their own use of language.

iz here sumware
“Koestler concluded that his hours spent by the prison window  scratching equations  had brought mystical insights into another realm of being.”

It is one of the few major novels whose protagonist is presented as being a mathematician.    Now, mathematicians are (if you please) god-like beings;  yet with very few exceptions (Galois,  Erdös ..) they do not lead colorful lives.  The man who settled Fermat’s Last Theorem, for instance, Andrew Wiles, is … um …. ahh… actually, I cannot think of a predicate -- he just is.

The quirky, philosophically-minded Intuitionist mathematician Brouwer, harbored similar “mysterian” views on ultimate indefinabilty.

In the stylistic spirit of minimalism (and of that pointilliste Wittgenstein), we shall begin with a Delphic  epigram:
Logicism:  a kind of reductionist minimalism.

Differentiable Penguins
Note that dismissive back-of-the-hand to mere “fun”,  which nonetheless figures first in the list of motivators, in the quotation from Ian Stewart  with which we began this essay.   For full-time professionals, mathematics is just too darn hard to be nothing but fun.  You don’t devote your entire life to crossword-puzzles or sudoku.

One frequently meets statements along these lines  (in the present instance, reporting the work of Freedman and Donaldson on h-cobordism):
     It’s true topologically, but not smoothly, for dimension four.
Are the post-modernists here positing some abstruse new varieties of truth -- topological and smooth?

"The fundamental theorem of enumeration, independently discovered by several anonymous cave dwellers, states that the number of elements in a set  is the sum over all elements of that set  of the constant function 1."


In focusing on definition, I am inadvertently revealing the déformation professionelle of one who used to earn his bread (or rather his hardtack; the profession is ill-paid) as a lexicographer.   For, rather than trying to say what a thing “is” (and here the Korzybskian strictures against the copula  have their full force), we may say, pragmatically rather than ontologically, what a thing is for.

Seen in that perspective, the ugling-duckling of a phrasing, “Why is mathematics?”, spreads the wings of a swan.

One day, for a wager, Cantor,
after much ribbing and banter …


Mathematicians are given  
to chiseled concision.
http://worldofdrjustice.blogspot.com/2014/01/language-and-math.html



Mathcat hath thpoken!



The very truth-predicate itself has been questioned within mathematics (albeit, by a rabble of Nominalists).   Thus, for a comparatively straightforward proposition “Catalan’s constant is transcendental”, a constructivist will not accept that this is either true or false.

... algebra, not in the sense of Galois or of André Weil, but of those unpleasant little sentences with x’s in them, relating to draining bathtubs which (against all reason) are simultaneously being replenished from the tap. http://worldofdrjustice.blogspot.com/2012/12/mathsex-updated-for-holiday-season.html




Our purpose is twofold;  indeed, the twin goals “can be thought of” as dual to each other.  The ostensible aim is (lightly) mathematical:  to provide pithy thumbnail sketches of complex fields of research.   The more substantial project takes place rather in the lexicographic ‘conjugate space’ which maps the items so defined.
http://worldofdrjustice.blogspot.com/2014/01/what-is-mathematics-expanded.html


Hard at work  in the math library





Compare a formulation we likewise favor, “Infinity is big.”   That epigram is double-edged.  First, it mimics the naïve astonishment that the novice feels, not only upon being introduced to the idea of infinity, but even large-but-finite things like a googolplex.  (As a child, I marveled over that one, much as I marveled over the brontosaurus, and for the same reasons.)



“Attempts to extend the geometry of second-order surfaces  and the algebra of quadratic forms  to objects of higher degrees  quickly leads to  the detritus of algebraic geometry, with its discouraging hierarchy of complicated degeneracies, and answers that can be computed only theoretically.”

Here, the answer to “What is Topology?”  is not simply knitted into a sampler and tacked to the drawing-room wall, but used as an actual heuristic for finding your way in a different field.

“Not a ‘triplex of mutually orthogonal rabbit-slices’, dammit!  I mean three  separate  rabbits !!”

~
~  Posthumous Endorsement ~
"If I were alive today, and in the mood for a mystery,
this is what I'd be reading"
(Ich bin Georg Cantor, and I approved this message.)
~        

Such ontological excrescences are even more thewless than “perfect” numbers, since at least the latter are independent of their inscriptional base.   (You can think of the writing of one of God’s own integers in any base  as representing a tragic demotion from the Platonic sphere, sort of like a soul’s being incarnated in the body of a frog.)

the topic of definite integrals -- painful but necessary, rather like a rectal exam

Which brings us back to the vexing question of the Riemann Hypothesis.   Its acceptance or non-acceptance cannot be left simply to each individual whim of the moment.    Rather, we must settle it the way all things are settled:  by majority vote (subject to Republican filibuster).

Such beauty and such elegance are perceptible only to the mind prepared -- otherwise it is like playing Bach to a baby.

The movie begins, as all Gauss sagas must, with the tale of how the young schoolboy, given a pensum  along with his fellows  of reckoning up the sum of the integers from one to a hundred, by finding a clever shortcut, rather than, as John von Neumann would have done, simply adding the series instantly in his head.  (That’s a joke.)

In practice, we know as little of this  as a starfish knows of the stars. 

Anthem of the Oligophreniacs:  “If I Only Had a Brain”

Intuitionism -- initially a sort of mathematical vegetarianism -- is by no means dead.

No new theorem of any importance came out of the immese effort at systematization of Nicolas Bourbaki

As so often when some movement of math has been seen streaking off westwards  out into the void, presumably never to been seen again by mortal man, it reappears shining in the east, reborn in some applicable form -- thus suggesting, you will notice, that the global topology of the noösphere is toroidal. 

“Too large a generalisation  leads to mere barrenness.  It is the large generalisation, limited by a happy particularity, which is the fruitful conception.”

The so-called “abstract” groups (MacLane himself uses the sneer-quotes here) mean to lift aloft from Groups of Transformations, in that they retain the laws (associativity, inverses, and all that) while becoming agnostic as to the nature of the elements …

Our bow to Gleason’s semantic precisionism  is not by way of fetishizing fine distinctions.

Trans-cosmic Pi Day

“Lobschevsky’s colleagues  failed to understand his work.  Since they did not want to write negative reviews, they simply ‘lost’ the text.”

In Vergleichende Anatomie der Engel (1825),  Fechner argued that the angels, as the most perfect beings, must be spherical, since the sphere is the most perfect form.

The final anguish  of the Asian bride  suggests the depth  of the Riemann Hypothesis.
       http://worldofdrjustice.blogspot.com/2014/01/a-dive-to-depths-expanded.html


Further choice morsels  here: