We prove that every polarity of PG(2k − 1, q), where k ≥ 2, gives rise to a design with the same parameters and the same intersection numbers as, but not isomorphic to PGk(2k, q). In particular, the case k = 2 yields a new family of quasi-symmetric designs. We also show that our construction provides an infinite family of counterexamples to Hamada’s conjecture, for any field of prime order p. P...

Current privacy preserving methods in data publishing always remove the individually identifying attribute first and then generalize the quasi-identifier attributes. They cannot take the individually identifying attribute into account. In fact, tuples will become vulnerable in the situation of multiple tuples per individual. In this paper, we analyze the individually identifying attribute in th...

Some curvature estimates are derived from geometrical data concerning quasi-conformality properties of some commuting linearly independent vector fields on a compact Riemannian manifold.

We introduce here a new approach to the study of m-quasi-invariants. This approach consists in representing m-quasi-invariants as N tuples of invariants. Then conditions are sought which characterize such N tuples. We study here the case of S3 m-quasi-invariants. This leads to an interesting free module of triplets of polynomials in the elementary symmetric functions e1, e2, e3 which explains c...

It is proved that any non-normable Fréchet space with a semisymmetric absolute basis is isomorphic to the space ω of all scalar sequences. A similar result is shown for quasi-homogeneous absolute bases. It is also proved that any nuclear Fréchet space with a semi-subsymmetric basis is isomorphic to ω.

In this paper we address the problem of a-migrativity (for a fixed a) for semicopulas, copulas and quasi-copulas. We introduce the concept of an a-sum of semicopulas. This new concept allows us to completely characterize a-migrative semicopulas and copulas. Moreover, a-sums also provide a means to obtain a partial characterization of a-migrative quasicopulas. 2010 Elsevier Inc. All rights reser...

Generalizing orthogonal arrays, a new class of arrays called quasiorthogonal arrays, are introduced and it is shown that fractional factorial plans represented by these arrays are universally optimal under a wide class of models. Some methods of construction of quasi-orthogonal arrays are also described.

We introduce quasi-cyclic codes of index 1 1 2 , construct such codes in terms of polynomials and matrices; and prove that the quasi-cyclic codes of index 1 1 2 are asymptotically good. MSC classes: 94B05, 94B65, 15B52.

Condition (C3) is called the 2–increasing property of C, and VC ([x1, x2]× [y1, y2]) is called the C–volume of the rectangle [x1, x2]× [y1, y2]. According to Sklar’s Theorem, copulas are functions that express the rankinvariant dependence between a pair of continuous random variables and, as such, they have been largely used in statistical applications . In particular, examples of copulas are g...