We prove that the categories of smooth and analytic unitary representations
of Banach--Lie supergroups are well-behaved under restriction functors, in the
sense that the restriction of a representation to an integral subsupergroup is
well-defined. We also prove that the category of analytic representations is
isomorphic to a subcategory of the category of smooth representations. These
facts are needed as a crucial first step to a rigorous treatment of the
analytic theory of unitary representations of Banach--Lie supergroups.
Let $G$ be a 1-connected Banach-Lie group or, more generally, a BCH--Lie
group. On the complex enveloping algebra $U_\C(\g)$ of its Lie algebra $\g$ we
define the concept of an analytic functional and show that every positive
analytic functional $\lambda$ is integrable in the sense that it is of the form
$\lambda(D) = \la \dd\pi(D)v, v\ra$ for an analytic vector $v$ of a unitary
representation of $G$. On the way to this result we derive criteria for the
integrability of *-representations of infinite dimensional Lie algebras of
unbounded operators to unitary group representations.
The construction of an infinite tensor product of the C*-algebra C_0(R) is
not obvious, because it is nonunital, and it has no nonzero projection. Based
on a choice of an approximate identity, we construct here an infinite tensor
product of C_0(R), denoted L_V. We use this to construct (partial) group
algebras for the full continuous unitary representation theory of the group
R^(N) = the infinite sequences with real entries, of which only finitely many
entries are nonzero.
The classical matter fields are sections of a vector bundle E with base
manifold M. The space L^2(E) of square integrable matter fields w.r.t. a
locally Lebesgue measure on M, has an important module action of C_b^\infty(M)
on it. This module action defines restriction maps and encodes the local
structure of the classical fields. For the quantum context, we show that this
module action defines an automorphism group on the algebra A, of the canonical
anticommutation relations on L^2(E), with which we can perform the analogous
localization. That is, the net structure of the CAR, A, w.r.t.
A unitary representation of a, possibly infinite dimensional, Lie group $G$
is called semi-bounded if the corresponding operators $i\dd\pi(x)$ from the
derived representations are uniformly bounded from above on some non-empty open
subset of the Lie algebra $\g$. In the first part of the present paper we
explain how this concept leads to a fruitful interaction between the areas of
infinite dimensional convexity, Lie theory, symplectic geometry (momentum maps)
and complex analysis.
Let $\cA$ be a commutative unital Banach algebra, $\g$ be a semisimple
complex Lie algebra and $G(\cA)$ be the 1-connected Banach--Lie group with Lie
algebra $\g \otimes \cA$. Then there is a natural concept of a parabolic
subgroup $P(\cA)$ of $G(\cA)$ and we obtain generalizations $X(\cA) :=
G(\cA)/P(\cA)$ of the generalized flag manifolds. In this note we provide an
explicit description of all homogeneous holomorphic line bundles over $X(\cA)$
with non-zero holomorphic sections.
Let $\cA$ be a commutative unital Banach algebra, $\g$ be a semisimple
complex Lie algebra and $G(\cA)$ be the 1-connected Banach--Lie group with Lie
algebra $\g \otimes \cA$. Then there is a natural concept of a parabolic
subgroup $P(\cA)$ of $G(\cA)$ and we obtain generalizations $X(\cA) :=
G(\cA)/P(\cA)$ of the generalized flag manifolds. In this note we provide an
explicit description of all homogeneous holomorphic line bundles over $X(\cA)$
with non-zero holomorphic sections.