March
28, 2003
Quidnunc
By the Numbers
Professor
of Mathematics Giuliana Davidoff, Peter Sarnak, and Alain Valette's
book Elementary Number Theory, Group Theory, and Ramanujan
Graphs has just appeared with Cambridge University Press.
Graphs are sets of points, called vertices, together with lines,
called edges, joining some of the pairs of vertices. They have
been studied intensively by mathematicians and are of interest
to engineers, theoretical biologists and computer scientists,
among others, who have used them to model all sorts of things:
networks, brain connections, economies, codes. The airline route
maps you find in the seat pockets in front of you on an airplane
and interstate maps on the inside of road atlases are graphs.
This book studies Ramanujan graphs, which connect many vertices
with a minimal number of edges but with reasonable redundancy
(such graphs are of intense interest to phone and computer companies).
"There have been a number of beautiful constructions of
infinite families of graphs that appear to be Ramanujan. However,
the proofs that they are Ramanujan are highly nontrivial. This
lovely little book presents some of these recently discovered
constructions together with full proofs," says Dean of Faculty
Donal O'Shea, Elizabeth T. Kennan Professor of Mathematics
and Computer Science. "The range of seemingly disparate
mathematical techniques and objects that make an appearance is
stunning: harmonic analysis, group representations, number theory,
spectral theory. The book evokes a deep sense of wonder and hints
at unexplored connections that lie just beyond our understanding."
Rock Research
Two MHC faculty members and four MHC students are presenting
geology research projects at a March meeting of the Geological
Society of America, Northeastern Section, and the Atlantic Geoscience
Society in Halifax, Nova Scotia, Canada. Approximately 500 geoscientists
are expected to attend. Jennifer Wright '03 and Associate
Professor of Geology Steven Dunn will present "Calcite-Graphite
Geothermometry and Mineral Equilibria in Amphibolite Facies Marbles
Near Bancroft, Ontario," a study of the temperatures attained
and chemical reactions that occurred among minerals and fluids
during a mountain-building event 1.1 billion years ago. Kay Achenbach
'03 and Dunn will present "Calcite-Graphite Carbon
Isotope Exchange in Low-Grade Marble," a study of how carbon-13
is partitioned between graphite (formed from metamorphism of organic
matter) and calcite in marble subjected to metamorphism at temperatures
of 450–500 degrees Celsius. Kristina Gross '03 and
Dunn, who investigated the timing of a little-known metamorphic
event in western Labrador (the Labradorian orogeny, about 1.6
billion years ago) with faculty from the University of Massachusetts
at Amherst and the University of Minnesota, will present "Electron
Microprobe Dating of Monazite in Constraining the Metamorphic
History of the Wilson Lake Terrane, Labrador." Phoebe Judge
'03 and Michelle Markley, Clare Boothe Luce Assistant Professor
of Geology, will present "Origin of Magnetic Fabrics in
Granites from the Cadillac Mountain Intrusive Complex, Maine,"
a study of the significance of magnetic fabrics in the 420-million-year-old
granitic magma chamber, which is exposed in Acadia National Park.
Living Spaces Dana Ganssle '03 is one of
ten artists from Connecticut, New York, New Jersey, and Massachusetts
whose work is on exhibit March 27–May 30 at the Institute
for Community Research (IRC) in Hartford, Connecticut. The exhibition
is part of "Living Spaces," a program of events in
which artists, researchers, urban planners, housing advocates,
and the public explore the interaction of physical and imagined
spaces. Ganssle, a spatial studies major studying art, dance,
and architecture, says this of her work Pay Per View, the installation
and performance piece included in the exhibition: "It is
literally an abstract frame (a window), which can be manipulated
to show the economic position a person is born into. The frame
is in reference to the concept of windows being indicators of
wealth and position, hence the name. I have three people performing.
They will be manipulating the installation, and putting the 'living'
into the space. One person will sit with their back to the action
the whole performance in reference to the abandonment I feel permeates
the living situation of many people in our society. I also think
that within the gallery setting the frames can act as an interesting
centerpiece to view the people visiting the exhibit." For
more information, contact Jill Chopyak Hogan, assistant director,
public programming and development, at 860-278-2044, x290.
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