358,741 research outputs found
Complements of nearly perfect graphs
A class of graphs closed under taking induced subgraphs is -bounded if
there exists a function such that for all graphs in the class, . We consider the following question initially studied in [A.
Gy{\'a}rf{\'a}s, Problems from the world surrounding perfect graphs, {\em
Zastowania Matematyki Applicationes Mathematicae}, 19:413--441, 1987]. For a
-bounded class , is the class -bounded (where
is the class of graphs formed by the complements of graphs from
)? We show that if is -bounded by the constant function
, then is -bounded by
and this is best possible. We show that for
every constant , if is -bounded by a function such that
for , then is -bounded. For every ,
we construct a class of graphs -bounded by whose
complement is not -bounded
Property and strong Property for unital -algebras
In this paper, we will give a thorough study of the notion of Property
for -algebras (as introduced by M.B. Bekka in \cite{Bek-T}) as well as a
slight stronger version of it, called "strong property " (which is also an
analogue of the corresponding concept in the case of discrete groups and type
-factors). More precisely, we will give some interesting equivalent
formulations as well as some permanence properties for both property and
strong property . We will also relate them to certain -type
properties of the unitary group of the underlying -algebra
SO(2,C) Invariant Discrete Gauge States in Liouville Gravity Coupled to Minimal Conformal Matter
We contruct the general formula for a set of discrete gauge states (DGS) in
c<1 Liouville theory. This formula reproduces the previously found c=1 DGS in
the appropriate limiting case. We also demonstrate the SO(2,C) invariant
structure of these DGS in the old covariant quantization of the theory. This is
in analogy to the SO(2,C) invariant ring structure of BRST cohomology of the
theory
Precise Predictions for Higgs Production in Neutralino Decays
Complete one-loop results, supplemented by two-loop Higgs propagator-type
corrections, are obtained for the class of processes chi^0_i->chi^0_j h_a in
the MSSM with CP-violating phases for parameters entering the process beyond
lowest order. The parameter region of the CPX benchmark scenario where a very
light Higgs boson is unexcluded by present data is analysed in detail. We find
that the decay chi^0_2->chi^0_1 h_1 may offer good prospects to detect such a
light Higgs boson.Comment: 4 pages, 3 figures; to appear in the proceedings of the 17th
International Conference on Supersymmetry and the Unification of Fundamental
Interactions (SUSY09), Boston, USA, 5-10 Jun 200
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