1,226 research outputs found
Feng-Rao decoding of primary codes
We show that the Feng-Rao bound for dual codes and a similar bound by
Andersen and Geil [H.E. Andersen and O. Geil, Evaluation codes from order
domain theory, Finite Fields Appl., 14 (2008), pp. 92-123] for primary codes
are consequences of each other. This implies that the Feng-Rao decoding
algorithm can be applied to decode primary codes up to half their designed
minimum distance. The technique applies to any linear code for which
information on well-behaving pairs is available. Consequently we are able to
decode efficiently a large class of codes for which no non-trivial decoding
algorithm was previously known. Among those are important families of
multivariate polynomial codes. Matsumoto and Miura in [R. Matsumoto and S.
Miura, On the Feng-Rao bound for the L-construction of algebraic geometry
codes, IEICE Trans. Fundamentals, E83-A (2000), pp. 926-930] (See also [P.
Beelen and T. H{\o}holdt, The decoding of algebraic geometry codes, in Advances
in algebraic geometry codes, pp. 49-98]) derived from the Feng-Rao bound a
bound for primary one-point algebraic geometric codes and showed how to decode
up to what is guaranteed by their bound. The exposition by Matsumoto and Miura
requires the use of differentials which was not needed in [Andersen and Geil
2008]. Nevertheless we demonstrate a very strong connection between Matsumoto
and Miura's bound and Andersen and Geil's bound when applied to primary
one-point algebraic geometric codes.Comment: elsarticle.cls, 23 pages, no figure. Version 3 added citations to the
works by I.M. Duursma and R. Pellikaa
Qudit Colour Codes and Gauge Colour Codes in All Spatial Dimensions
Two-level quantum systems, qubits, are not the only basis for quantum
computation. Advantages exist in using qudits, d-level quantum systems, as the
basic carrier of quantum information. We show that color codes, a class of
topological quantum codes with remarkable transversality properties, can be
generalized to the qudit paradigm. In recent developments it was found that in
three spatial dimensions a qubit color code can support a transversal
non-Clifford gate, and that in higher spatial dimensions additional
non-Clifford gates can be found, saturating Bravyi and K\"onig's bound [Phys.
Rev. Lett. 110, 170503 (2013)]. Furthermore, by using gauge fixing techniques,
an effective set of Clifford gates can be achieved, removing the need for state
distillation. We show that the qudit color code can support the qudit analogues
of these gates, and show that in higher spatial dimensions a color code can
support a phase gate from higher levels of the Clifford hierarchy which can be
proven to saturate Bravyi and K\"onig's bound in all but a finite number of
special cases. The methodology used is a generalisation of Bravyi and Haah's
method of triorthogonal matrices [Phys. Rev. A 86 052329 (2012)], which may be
of independent interest. For completeness, we show explicitly that the qudit
color codes generalize to gauge color codes, and share the many of the
favorable properties of their qubit counterparts.Comment: Authors' final cop
High-entropy dual functions over finite fields and locally decodable codes
We show that for infinitely many primes p, there exist dual functions of order k over Fnp that cannot be approximated in L∞-distance by polynomial phase functions of degree k−1. This answers in the negative a natural finite-field analog of a problem of Frantzikinakis on L∞-approximations of dual functions over N (a.k.a. multiple correlation sequences) by nilsequences
FRUSTRATION: PHYSICO-CHEMICAL PREREQUISITES FOR THE CONSTRUCTION OF A SYNTHETIC CELL
To construct a synthetic cell we need to understand the rules that
permit life. A central idea in modern biology is that in addition to
the four entities making reality, matter, energy, space and time, a fifth
one, information, plays a central role. As a consequence of this central
importance of the management of information, the bacterial cell is
organised as a Turing machine, where the machine, with its compartments
defining an inside and an outside and its metabolism, reads and
expresses the genetic program carried by the genome. This highly
abstract organisation is implemented using concrete objects and dynamics,
and this is at the cost of repeated incompatibilities (frustration),
which need to be sorted out by appropriate «patches». After describing
the organisation of the genome into the paleome (sustaining and propagating
life) and the cenome (permitting life in context), we describe
some chemical hurdles that the cell as to cope with, ending with the
specific case of the methionine salvage pathwa
Court of Appeal found no love for Topshop tank: the image right that dare not speak its name
This article contains an analysis of the first instance and appeal decisions of the "Rihanna" case. In particular, the authors consider the substantive law of passing off in the context of the unauthorised use of a celebrity’s image on a Topshop tank vest top. This is followed by a discussion of the consequences of the case for celebrities, consumers and stakeholders in the entertainment and fashion industries
Ethical challenges in argumentation and dialogue in a healthcare context.
As the average age of the population increases, so too do the number of people living with chronic illnesses. With limited resources available, the development of dialogue-based e-health systems that provide justified general health advice offers a cost-effective solution to the management of chronic conditions. It is however imperative that such systems are responsible in their approach. We present in this paper two main challenges for the deployment of e-health systems, that have a particular relevance to dialogue and argumentation: collecting and handling health data, and trust. For both challenges, we look at specific issues therein, outlining their importance in general, and describing their relevance to dialogue and argumentation. Finally, we go on to propose six recommendations for handling these issues, towards addressing the main challenges themselves, that act both as general advice for dialogue and argumentation research in the e-health domain, and as a foundation for future work on this topic
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