Sven Raum, Stockholm University
"Superrigidity for group operator algebras"
It
is
a
classical
problem
to
recover
a
discrete
group
from
various
rings
or
algebras
associated
with
it,
such
as
the
integral
group
ring.
By
analogy,
in
an
operator
algebraic
framework
we
want
to
recover
torsion-free
groups
from
certain
topological
completions
of
the
complex
group
ring,
such
as
the
reduced
group
C*-algebra.
Groups
for
which
this
is
possible
are
called
C*-superrigid.
I
will
start
this
talk
with
a
discussion
of
how
a
group
can
be
recovered
from
its
group
rings,
before
I
introduce
the
reduced
group
C*-algebras
and
describe
the
state-of-the-art
in
C*-superrigidity.
I
will
end
with
a
short
account
on
other
kinds
of
superrigidity
for
group
operator
algebras
putting
the
subject
into
a
bigger
perspective.
MC 5501