Joe,
Thank you for your thoughts on multiplication. They were helpful and
timely as I prepared my talk:
http://www.ms.lt/sodas/Book/DiscoveryInMathematics
"Discovery in Mathematics: A System of Deep Structure"
Please see my diagram and discussion at the end. It's based on Maria
Droujkova's and her Natural Math team's work on the many different
meanings of ordinary multiplication.
Also, please see my discussion of the four different geometries. I know
nothing about them but my approach is able to help bring out their
importance, though. Symplectic geometry preserves "areas" which is
probably the same as what you mean by "volumes", yes?
I look forward to learning and thinking a lot more about these subjects.
Thank you and all for your insights!
Andrius
Andrius Kulikauskas
m...@ms.lt
+370 607 27 665
-----------------------------------
Kirby et al,
The more I think about "multiplication", the more I think the term is
being abused.
What we call "scalar" multiplication seems to capture the essence of one
understanding: multiplication as repeated addition, the Peano definition.
Physically, this often take the form of a "production" equation: rate *
time = product; e.g. 60 miles per hour times 4 hours = 240 miles.
(Which, BTW, is the operation of extracting the distance component from
a speed, not constructing a composite of distance and time.)
But then there are all sorts of other multiplications.
My question: what do you call "volume conserving" transformations"? Is
there a "branch" of mathematics devoted to their study?
Clearly translations and rotations fall in this category, but only
certain kinds of "stretching".
But more generally, consider the shapes assumed by a blob of viscous
liquid (of uniform density) tumbling through space or distributing
itself over an uneven surface,
My intuition is that "volume" is conserved by nature, even
pseudo-volumes composed of multiple types such as kilogram meters or
volt amperes.
And taking a cue from Geometric Algebra, "rotations" are not so much
"multiplications" as "additions" of arcs.
As for addition, we see in "vector addition" and more generally in
molecular structure,
that physical "additions" include a component of direction as well as a
component of magnitude, so we might call this "construction".
So we have a "constructive" operation of addition, extended to scalar
multiplication;
And a "transformative" operation traditionally called "multiplication"
but which I would rename as, well, "transformation".
So my "new math" would have operators of "construction" and
"transformation", which both can be considered forms of "arrangement",
which probably ends up in group theory!.
If I were a mathematician, I would probably be able to develop such
ideas into a "grand unification of mathematics"!
But for now, I'm still wrestling with the idea that the exponentiation
operator has two inverses
and yields (at least) two new kinds of irrational numbers: radical and
complex.
Complex seems to come from the dimensionality-increasing nature of
"multiplication",
and radical from the notion that "root taking" should be closed and
single-valued, i.e. all n factors of x^n equal.
[Eureka! In my own mind, I had never crystallized the idea into such
statements until just now!]
Coupled with the idea that the algebraic sign of the integers is just
the 1D version of direction,
we have the concept that "numbers"--or more generally, quantities--have
both a magnitude (arithmetic) and a directional (geometric) component.
So we need to put Euclid and Peano together!
But back to multiplication.
As I have been saying, I think we have been looking at "multiplication"
thru the wrong end of the telescope.
I say "nature" starts with multi-dimensional hyper-volumes, and we
humans observe and compute the projections.
Which led to my original question: is there a mathematics of "volume
conserving" (constant integral) transformations?
Joe Austin