Differential
topology
Doug
Park
is
a
specialist
in
differential
topology.
His
primary
study
involves
the
classification
of
all
four-dimensional
shapes,
computations
of
their
invariants,
and
methods
of
constructing
brand
new
four-dimensional
shapes
from
old
shapes
via
geometric
“surgery.”
His
research
papers
bring
to
bear
the
tools
of
modern
geometers
such
as:
gluing
formulae,
branched
coverings,
surgery,
and
symbolic
computation.