3,552 research outputs found
Calabi-Yau structures on topological Fukaya categories
We develop a local-to-global formalism for constructing Calabi-Yau structures
for global sections of constructible sheaves or cosheaves of categories. The
required data - an isomorphism of the sheafified Hochschild homology with the
topological dualizing sheaf - specializes to the classical notion of
orientation when applied to the category of local systems on a manifold. We
apply this construction to the cosheaves on arboreal skeleta arising in the
microlocal approach to the A-model.Comment: 88 pages, 15 figure
A support theorem for Hilbert schemes of planar curves
Consider a family of integral complex locally planar curves whose relative
Hilbert scheme of points is smooth. The decomposition theorem of Beilinson,
Bernstein, and Deligne asserts that the pushforward of the constant sheaf on
the relative Hilbert scheme splits as a direct sum of shifted semisimple
perverse sheaves. We will show that no summand is supported in positive
codimension. It follows that the perverse filtration on the cohomology of the
compactified Jacobian of an integral plane curve encodes the cohomology of all
Hilbert schemes of points on the curve. Globally, it follows that a family of
such curves with smooth relative compactified Jacobian ("moduli space of
D-branes") in an irreducible curve class on a Calabi-Yau threefold will
contribute equally to the BPS invariants in the formulation of Pandharipande
and Thomas, and in the formulation of Hosono, Saito, and Takahashi.Comment: 13 pages. (v2 updated to match published version.
Half-Duplex or Full-Duplex Relaying: A Capacity Analysis under Self-Interference
In this paper multi-antenna half-duplex and full-duplex relaying are compared
from the perspective of achievable rates. Full-duplexing operation requires
additional resources at the relay such as antennas and RF chains for
self-interference cancellation. Using a practical model for the residual
self-interference, full-duplex achievable rates and degrees of freedom are
computed for the cases for which the relay has the same number of antennas or
the same number of RF chains as in the half-duplex case, and compared with
their half-duplex counterparts. It is shown that power scaling at the relay is
necessary to maximize the the degrees of freedom in the full-duplex mode.Comment: New references added and some typos have been corrected. 6 Pages, 5
Figures. Accepted for publication in the CISS-201
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