9,144 research outputs found
Computing the Ball Size of Frequency Permutations under Chebyshev Distance
Let be the set of all permutations over the multiset
where
. A frequency permutation array (FPA) of minimum distance is a
subset of in which every two elements have distance at least .
FPAs have many applications related to error correcting codes. In coding
theory, the Gilbert-Varshamov bound and the sphere-packing bound are derived
from the size of balls of certain radii. We propose two efficient algorithms
that compute the ball size of frequency permutations under Chebyshev distance.
Both methods extend previous known results. The first one runs in time and space. The second one runs in time and
space. For small constants and ,
both are efficient in time and use constant storage space.Comment: Submitted to ISIT 201
On the Emergence and Evolution of Mark-up Middlemen: An Inframarginal Model
This paper is aimed to provide an economic interpretation on the emergence and evolution of the specialised middlemen whose duty is to facilitate the transactions of goods and services in an economy. In a general equilibrium framework, the emergence and evolution of the specialised middlemen conforms to Adam Smithâs insight of deepening specialisation and the division of labour with the improvement in institutions and/or transaction technologies. Consequently, the emergence and the growth of the intermediation sector in both absolute and relative terms, the expansion of the network which provides transaction services, the evolution of market structure from autarky towards division of labour, the improvement in productivity, the reduction in wholesaling-retailing price dispersion, will be realised in concurrencymiddlemen, transaction efficiency, inframarginal economics
\Lambda_b Lifetime from the HQET Sum Rule
The HQET sum rule analysis for the \Lambda_b matrix element of the four-quark
operator relevant to its lifetime is reported. Our main conclusion is that the
lifetime ratio \tau(\Lambda_b)/\tau(B^0) can be as low as 0.91.Comment: 5 pages, latex, no figures, uses sprocl.sty (included). Talk by C.
Liu at Int. Conf. on Flavor Phys., Zhang-Jia-Jie, 31/5-6/6 200
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