For any integer ρ ≥ 1 and for any prime power q, the explicit construction of a infinite family of completely regular (and completely transitive) q-ary codes with d = 3 and with covering radius ρ is given. The intersection array is also computed. Under the same conditions, the explicit construction of an infinite family of q-ary uniformly packed codes (in the wide sense) with covering radius ρ,...

We study the remarkable Saxl conjecture which states that tensor squares of certain irreducible representations of the symmetric groups Sn contain all irreducibles as their constituents. Our main result is that they contain representations corresponding to hooks and two row Young diagrams. For that, we develop a new sufficient condition for the positivity of Kronecker coefficients in terms of c...

Integer-translates of compactly supported univariate refinable functions φi , such as cardinal B-splines, have been used extensively in computational mathematics. Using certain appropriate direction vectors, the notion of (multivariate) box splines can be generalized to (non-tensor-product) compactly supported multivariate refinable functions from the φi ’s. The objective of this paper is to in...

In this paper we define ?-independent (a weak-version of independence), Kronecker and dissociate sets on hypergroups and study their properties and relationships among them and some other thin sets such as independent and Sidon sets. These sets have the lacunarity or thinness property and are very useful indeed. For example Varopoulos used the Kronecker sets to prove the Malliavin theorem. In t...

Given two graphs G1 and G2, the Kronecker product G1 ⊗G2 of G1 and G2 is a graph which has vertex set V (G1⊗G2) = V (G1)×V (G2) and edge set E(G1 ⊗ G2) = {(u1, v1)(u2, v2) : u1u2 ∈ E(G1) and v1v2 ∈ E(G2)}. ∗ Research was partially supported by the National Nature Science Foundation of China (No. 11171207) and the Key Programs of Wuxi City College of Vocational Technology (WXCY2012-GZ-007). † Co...

Let k¿2; n=2+1; and let m0; : : : ; mk−1 each be a multiple of n. The graph Cm0×· · ·×Cmk−1 consists of isomorphic connected components, each of which is (n − 1)-regular and admits of a vertex partition into n smallest independent dominating sets. Accordingly, (independent) domination number of each connected component of this graph is equal to (1=n)th of the number of vertices in it. ? 2001 El...

Irreducible projective representations of the translation group of a finite N×N two-dimensional lattice can be labeled by symbols 〈n, l;q〉, where N = νn, gcd(l, n) = 1 and q denotes an irreducible representation of Z ν . Obtained matrices are n-dimensional and the factor system of this representation does not depend on q and equals m (l) n ([n1, n2], [n ′ 1, n ′ 2]) = exp(2πi ln2n ′ 1/N). For a...

We consider the iterative solution of linear systems arising from four convection–diffusion model problems: scalar convection–diffusion problem, Stokes problem, Oseen problem and Navier–Stokes problem. We design preconditioners for these model problems that are based on Kronecker product approximations (KPAs). For this we first identify explicit Kronecker product structure of the coefficient ma...

Many very large Markov chains can be modelled e ciently as stochastic automata networks (SANs). A SAN is composed of individual automata which, for the most part, act independently, requiring only infrequent interaction. SANs represent the generator matrix Q of the underlying Markov chain compactly as the sum of Kronecker products of smaller matrices. Thus, storage savings are immediate. The be...

X. Zhan has conjectured that the spectral radius of the Hadamard product of two square nonnegative matrices is not greater than the spectral radius of their ordinary product. We prove Zhan’s conjecture, and a related inequality for positive semidefinite matrices, using standard facts about principal submatrices, Kronecker products, and the spectral radius.