Tropical
Geometry
is
a
systematic
development
of
the
very
well-known
fundamental
con-
cept,
“degeneration”.
In
this
talk,
I
will
make
this
statement
precise,
focusing
on
an
explicit
example,
Severi
varieties.
Severi
varieties
are
classical
objects
in
algebraic
geometry
which
parametrize
plane
curves
with
nodal
singularities.
Understanding
Severi
varieties
in
the
view
of
Tropical
geometry,
we
can
obtain
purely
combinatorial
results.