10,183 research outputs found
Theoretical Overview on the Flavor Issues of Massive Neutrinos
We present an overview on some basic properties of massive neutrinos and
focus on their flavor issues, including the mass spectrum, flavor mixing
pattern and CP violation. The lepton flavor structures are explored by taking
account of the observed value of the smallest neutrino mixing angle
\theta_{13}. The impact of \theta_{13} on the running behaviors of other flavor
mixing parameters is discussed in some detail. The seesaw-induced enhancement
of the electromagnetic dipole moments for three Majorana neutrinos is also
discussed in a TeV seesaw scenario.Comment: References added. arXiv admin note: text overlap with
arXiv:1203.1672, arXiv:1201.2543, arXiv:1203.311
Optimal locally repairable codes of distance and via cyclic codes
Like classical block codes, a locally repairable code also obeys the
Singleton-type bound (we call a locally repairable code {\it optimal} if it
achieves the Singleton-type bound). In the breakthrough work of \cite{TB14},
several classes of optimal locally repairable codes were constructed via
subcodes of Reed-Solomon codes. Thus, the lengths of the codes given in
\cite{TB14} are upper bounded by the code alphabet size . Recently, it was
proved through extension of construction in \cite{TB14} that length of -ary
optimal locally repairable codes can be in \cite{JMX17}. Surprisingly,
\cite{BHHMV16} presented a few examples of -ary optimal locally repairable
codes of small distance and locality with code length achieving roughly .
Very recently, it was further shown in \cite{LMX17} that there exist -ary
optimal locally repairable codes with length bigger than and distance
propositional to .
Thus, it becomes an interesting and challenging problem to construct new
families of -ary optimal locally repairable codes of length bigger than
.
In this paper, we construct a class of optimal locally repairable codes of
distance and with unbounded length (i.e., length of the codes is
independent of the code alphabet size). Our technique is through cyclic codes
with particular generator and parity-check polynomials that are carefully
chosen
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