Links
This page will give a thematic organization of the topics discussed at
this REU, linking to other webpages where appropriate. Here is an
list of classes of fractals we might study, in decreasing order of
generality:
- Fractals. Any old fractal. Right now, we can't really say
anything about differential equations on arbitrary fractals.
- Iterated Function Systems. These are the fractals obtained from
iterated contractive mappings. In general, we only understand these
through computational approximations by open sets, for which
differential equations can be computed as in the non-fractal case. For
some very interesting results on the Sierpinski Carpet and the
Octagasket, see Stacey's webpage.
- Post-Critically Finite Iterated Function Systems. This
essentially means that the ifs is finitely ramified, although the actual
definition is a little more involved. There are many abstract analytic
results for these fractals. Work by Sabot and Kigami in particular was
consulted for my project. There are very few special cases, however,
where much more is known than these general results..
- Maximally Connected Post-Criticallly Finite Iterated Function
Systems. This was my project. If anyone other than Luke Rogers, Bob
Strichartz, and myself is studying these fractals, I would like to know
about it.
- The Sierpinski 3-Gasket...
- ... with an Energy measure. Alex and Naotaka studied this
extensively from a computational perspective and have some excellent
conjectures about the spectrum of the Kusuoka Laplacian. Their website
is not up yet, so far as I know.
- ... with the standard graph energy with conductances and
varied contractive mappings. Anna and Baris did extensive work on the
spectrum of the Laplacian for various twisted gaskets. Their work can
be found here.
- ... with constant conductances. A great deal is
understood about the Laplacian and a select few other differential
equation concepts on these gaskets. Jessie worked on defining and
computing a gradient for eigenfunctions of the Laplacian. Zuhair and
Edward investigated Schroedinger equations with various potentials, and
in particular did a promising study on what exactly x^2 is as a function
on SG3. I haven't seen websites for any of these yet.
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