"A heavy
warning used to be given that pictures are not rigorous; this has never had
its
bluff called and has permanently frightened its victims." –
Littlewood's Miscellany
Report
of
Science
at
Williams
2003-2004
REPORT
OF
SCIENCE
AT
WILLIAMS
COLLEGE
2003
–
2004
A
RECORD OF THE PROFESSIONAL ACTIVITIES
OF
FACULTY AND STUDENTS IN THE
NATURAL
SCIENCES
Williamstown,
Massachusetts
2004
Cover:
The underlying theme behind the images is the theory of
particle collisions. The shapes show the different ways particles can move and
collide on a circle and a line. Figure 1 shows two different ways of keeping
track of three particles on a circle. It turns out that both of these ways,
though visually different, yield the same mathematical object. Both objects are
made up of 60 identical copies of a polyhedron known as the
"associahedron,” an object that shows up in string theory.
Front Cover
The four figures in Figure 2 show different
representations of the 4-dimensional version of the associahedron. Although the
images look different, a simple argument shows that all four pictures are the
same. The image surrounding each polytope, drawn with three black and four
colored particles (distributed in different combinations) show the configuration
space associated to each object. The black particles are fixed whereas the color
particles are allowed to move and interact with each other.
The top of Figure 3 shows the arrangement of five
3-dimensional polyhedra gluing together in another configuration space. This
space was discovered in Professor Satyan Devadoss’s SMALL 2003 summer
undergraduate research group. The gluing that tells us how these objects should
fit together is associated with the arrangement of four centrally symmetric
particles on a line (three regular and one "thick" particle). This is shown in
the bottom of Figure 3.
The
Science Executive Committee wishes to express its gratitude to the extensive
efforts of all the science departmental executive assistants in preparing
contributions for this publication, and to
Kate Fletcher, administrative
assistant at the Science Center, for assembling this material in its final
form.
Editor: Dr. Bryce
Babcock

This document is printed on recycled paper.
Williams
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regulations thereunder, in the education programs or activities which it
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activities. Inquiries concerning the College’s non-discrimination
policies may be referred to the Dean of the College, Hopkins Hall, Williamstown,
MA 01267.