共查询到20条相似文献,搜索用时 144 毫秒
1.
Vladimir I. Levenshtein 《Designs, Codes and Cryptography》1997,12(2):131-160
A system of (Boolean) functions in
variables is called randomized if the functions preserve the property of their variables to be independent and uniformly distributed random variables. Such a system is referred to as
-resilient if for any substitution of constants for any
variables, where 0 i t, the derived system of functions in
variables will be also randomized. We investigate the problem of finding the maximum number
of functions in
variables of which any
form a
-resilient system. This problem is reduced to the minimization of the size of certain combinatorial designs, which we call split orthogonal arrays. We extend some results of design and coding theory, in particular, a duality in bounding the optimal sizes of codes and designs, in order to obtain upper and lower bounds on
. In some cases, these bounds turn out to be very tight. In particular, for some infinite subsequences of integers
they allow us to prove that
,
,
,
,
. We also find a connection of the problem considered with the construction of unequal-error-protection codes and superimposed codes for multiple access in the Hamming channel. 相似文献
2.
Massimo Giulietti Fernanda Pambianco Fernando Torres Emanuela Ughi 《Designs, Codes and Cryptography》2002,25(3):237-246
We point out an interplay between
-Frobenius non-classical plane curves and complete
-arcs in
. A typical example that shows how this works is the one concerning an Hermitian curve. We present some other examples here which give rise to the existence of new complete
-arcs with parameters
and
being a power of the characteristic. In addition, for q a square, new complete
-arcs with either
and
or
and
are constructed by using certain reducible plane curves. 相似文献
3.
In this paper we show that the support of the codewords of each type in the Kerdock code of length 2m over Z4 form 3-designs for any odd integer
. In particular, twonew infinite families of 3-designs are obtained in this constructionfor any odd integer
. In particular, twonew infinite families of 3-designs are obtained in this constructionfor any odd integer
, whose parameters are
,and
. 相似文献
4.
Consider a path-integral
which is the solution to a diffusion version of the generalized Schro¨dinger's equation
. Here
, where A is an infinitesimal generator of a strongly continuous Markov Semigroup corresponding to the diffusion process
. For
and V replaced by
one obtains
, which represents a quantum mechanical Hamiltonian corresponding to a particle of mass 1 (in atomic units) subject to interaction with potential V. This paper is concerned with computer calculations of the second eigenvalue of
by generating a large number of trajectories of an ergodic diffusion process. 相似文献
5.
Koichi Betsumiya T. Aaron Gulliver Masaaki Harada 《Designs, Codes and Cryptography》2003,28(2):171-186
In this paper, it is shown that extremal (Hermitian) self-dual codes over
2 ×
2 exist only for lengths 1, 2, 3, 4, 5, 8 and 10. All extremal self-dual codes over
2 ×
2 are found. In particular, it is shown that there is a unique extremal self-dual code up to equivalence for lengths 8 and 10. Optimal self-dual codes are also investigated. A classification is given for binary [12, 7, 4] codes with dual distance 4, binary [13, 7, 4] codes with dual distance 4 and binary [13, 8, 4] codes with dual distance 4. 相似文献
6.
This article improves results of Hamada, Helleseth and Maekawa on minihypers in projective spaces and linear codes meeting the Griesmer bound.In [10,12],it was shown that any
-minihyper, with
, where
, is the disjoint union of
points,
lines,...,
-dimensional subspaces. For q large, we improve on this result by increasing the upper bound on
non-square, to
non-square,
square,
, and (4) for
square, p prime, p<3, to
. In the case q non-square, the conclusion is the same as written above; the minihyper is the disjoint union of subspaces. When q is square however, the minihyper is either the disjoint union of subspaces, or the disjoint union of subspaces and one subgeometry
. For the coding-theoretical problem, our results classify the corresponding
codes meeting the Griesmer bound. 相似文献
7.
Tatsuya Maruta 《Designs, Codes and Cryptography》2001,22(2):165-177
There do not exist
codes over the Galois field GF
attaining the Griesmer bound for
for
andfor
for
. 相似文献
8.
Judita Lihová 《Czechoslovak Mathematical Journal》1999,49(1):67-80
Let
be a partially ordered set, Int
the system of all (nonempty) intervals of
partially ordered by the set-theoretical inclusion
. We are interested in partially ordered sets
with Int
isomorphic to Int
. We are going to show that they correspond to couples of binary relations on A satisfying some conditions. If
is a directed partially ordered set, the only
with Int
isomorphic to Int
are
corresponding to direct decompositions
of
(
denotes the dual of
. The present results include those presented in the paper [11] by V. Slavík. Systems of intervals, particularly of lattices, have been investigated by many authors, cf. [1]–[11]. 相似文献
9.
D. M. Smirnov 《Algebra and Logic》2003,42(2):136-146
We continue to study interrelations between permutative varieties and the cyclic varieties defined by cycles of the form
. A criterion is given determining whether a cyclic variety
is interpretable in
. For a permutation
without fixed elements, it is stated that a set of primes
for which
is interpretable in
in the lattice
is finite. It is also proved that for distinct primes
, the Helly number of a type
in
coincides with dimension of the dual type
and equals
. 相似文献
10.
Let
be a sequence of complex numbers such that
as
. For
close to the imaginary axis, upper bounds of the indicator of a nonzero entire function of exponential type with minimal growth vanishing on
is obtained. These bounds give sufficient conditions for the system of exponents
to be incomplete in an unbounded domain in
. 相似文献
11.
Joseph H. Silverman 《Designs, Codes and Cryptography》2000,20(1):5-40
Let
be an elliptic curve defined over a finite field, and let
be two points on E. The Elliptic Curve Discrete Logarithm Problem (ECDLP) asks that an integer m be found so that S=mT in
. In this note we give a new algorithm, termed the Xedni Calculus, which might be used to solve the ECDLP. As remarked by Neal Koblitz, the Xedni method is also applicable to the classical discrete logarithm problem for
and to the integer factorization problem. 相似文献
12.
Suppose that k and l are integers such that
and
, M
k is a set of numbers without kth powers, and
. In this paper, we obtain asymptotic estimates of the sums
over
相似文献
13.
We study a version of the Gauss map
for a surface
immersed in
and prove an analog of the Ruh--Vilms theorem which states that this map is harmonic iff
has a constant mean curvature. As a corollary, we conclude that an embedded flat torus
with constant mean curvature is a spherical Delonay surface. 相似文献
14.
Izu Vaisman 《Annals of Global Analysis and Geometry》2001,19(3):209-234
The transversal twistor space of a foliation
of an even codimension is the bundle
of the complex structures of the fibers of the transversalbundle of
. On
there exists a foliation
by covering spaces of the leaves of
, and any Bottconnection of
produces an ordered pair
of transversal almost complex structures of
. The existence of a Bott connection which yields a structure
1 that is projectable to the space of leaves isequivalent to the fact that
is a transversallyprojective foliation. A Bott connection which yields a projectablestructure
2 exists iff
isa transversally projective foliation which satisfies a supplementarycohomological condition, and, in this case,
1is projectable as well.
2 is never integrable.The essential integrability condition of
1 isthe flatness of the transversal projective structure of
. 相似文献
15.
Let
and
be Hausdorff topological vector spaces over the field
, let
be a bilinear functional, and let
be a non-empty subset of
. Given a set-valued map
and two set-valued maps
, the generalized bi-quasi-variational inequality (GBQVI) problem is to find a point
and a point
such that
and
for all
and for all
or to find a point
a point
and a point
such that
and
for all
. The generalized bi-quasi-variational inequality was introduced first by Shih and Tan [8] in 1989. In this paper we shall obtain some existence theorems of generalized bi-quasi-variational inequalities as application of upper hemi-continuous operators [4] in locally convex topological vector spaces on compact sets. 相似文献
16.
Peter V. Danchev 《Czechoslovak Mathematical Journal》2002,52(1):129-140
Suppose
is a commutative ring with identity of prime characteristic
and
is an arbitrary abelian
-group. In the present paper, a basic subgroup and a lower basic subgroup of the
-component
and of the factor-group
of the unit group
in the modular group algebra
are established, in the case when
is weakly perfect. Moreover, a lower basic subgroup and a basic subgroup of the normed
-component
and of the quotient group
are given when
is perfect and
is arbitrary whose
is
-divisible. These results extend and generalize a result due to Nachev (1996) published in Houston J. Math., when the ring
is perfect and
is
-primary. Some other applications in this direction are also obtained for the direct factor problem and for a kind of an arbitrary basic subgroup. 相似文献
17.
Alexei Ashikhmin 《Designs, Codes and Cryptography》1998,14(2):107-126
The definition of generalized Hamming weights (GHW) for linear codes over Galois rings is discussed. The properties of GHW for Galois ring linear codes are stated. Upper and existence bounds for GHW of
– linear codes and a lower bound for GHW of the Kerdock code over
– are derived. GHW of some
– linear codes are determined. 相似文献
18.
Hendrik Grundling 《Acta Appl Math》1997,46(2):107-145
Given an inductive limit group
where each
is locally compact, and a continuous two-cocycle
, we construct a C*-algebra
group algebra
is imbedded in its multiplier algebra
, and the representations of
are identified with the strong operator continuous
of G. If any of these representations are faithful, the above imbedding is faithful. When G is locally compact,
is precisely
, the twisted group algebra of G, and for these reasons we regard
in the general case as a twisted group algebra for G. Applying this construction to the CCR-algebra over an infinite dimensional symplectic space (S,\,B),we realise the regular representations as the representation space of the C*-algebra
, and show that pointwise continuous symplectic group actions on (S,\, B) produce pointwise continuous actions on
, though not on the CCR-algebra. We also develop the theory to accommodate and classify 'partially regular' representations, i.e. representations which are strong operator continuous on some subgroup H of G (of suitable type) but not necessarily on G, given that such representations occur in constrained quantum systems. 相似文献
19.
Hiroshi Suzuki 《Journal of Algebraic Combinatorics》1998,7(2):165-180
It is well known that imprimitive P-polynomial association schemes
with
are either bipartite or antipodal, i.e., intersection numbers satisfy either
for all
for all
. In this paper, we show that imprimitive
-polynomial association schemes
with
are either dual bipartite or dual antipodal, i.e., dual intersection numbers satisfy either
. 相似文献
20.
Suppose that
,
, and
are three discrete probability distributions related by the equation (E):
, where
denotes the k-fold convolution of
In this paper, we investigate the relation between the asymptotic behaviors of
and
. It turns out that, for wide classes of sequences
and
, relation (E) implies that
, where
is the mean of
. The main object of this paper is to discuss the rate of convergence in this result. In our main results, we obtain O-estimates and exact asymptotic estimates for the difference
. 相似文献