For a smooth surface S in P 3 of degree d and for positive integers n, δ, the Severi variety V 0 n,δ (S) is the subvariety of the linear system |O S (n)| which parametrizes curves with δ nodes. We show that for S general, n ≥ d and for all δ with 0 ≤ δ ≤ dim(|O S (n)|), then V 0 n,δ (S) has at least one component which is reduced, of the expected dimension dim(|O S (n)|) − δ. We also construct ...

Let F 2ν δ l q be a 2ν δ l -dimensional vector space over the finite field Fq. In this paperwe assume that Fq is a finite field of odd characteristic, and O2ν δ l, Δ Fq the singular orthogonal groups of degree 2ν δ l over Fq. Let M be any orbit of subspaces under O2ν δ l, Δ Fq . Denote by L the set of subspaces which are intersections of subspaces in M, where we make the convention that the int...

Let S and Δ be numerical semigroups. A semigroup is an I(Δ)-semigroup if \ {0} ideal of Δ. We denote by ℐ (Δ) = {S | I(Δ)-semigroup}, we say that extension ∈ (Δ). In this work, present algorithm to build all the extensions a nu-merical semigroup. recursively ℐ0(ℕ) ℕ, ℐ1(ℕ) ℐ(ℕ) ℐk+1(ℕ) ℐ(ℐ k(ℕ)) for k ℕ. The complexity minimum set {k ℕ ℐk(ℕ)}. addition, introduce compute semigroups with fixed m...

Given a double-well potential F , a Z-periodic function H, small and with zero average, and ε > 0, we find a large R, a small δ and a function Hε which is ε-close to H for which the following two problems have solutions: 1. Find a set Eε,R whose boundary is uniformly close to ∂BR and has mean curvature equal to −Hε at any point, 2. Find u = uε,R,δ solving −δ∆u+ F (u) δ + c0 2 Hε = 0, such that ...

In this paper, we introduce upper and lower almost δ-M -continuous multifunctions as a generalization of δ-M -continuous multifunctions. Some characterizations and several properties concerning upper and lower almost δ-M -continuous multifunctions are obtained. The relationships between upper δ-M -continuous multifunctions and upper almost δ-M -continuous multifunctions are also discussed. Math...

We study the spectral radius of connected non-regular graphs. Let λ1(n,Δ) be the maximum spectral radius among all connected non-regular graphs with n vertices and maximum degree Δ. We prove that Δ− λ1(n,Δ)=Θ(Δ/n). This improves two recent results by Stevanović and Zhang, respectively. © 2007 Elsevier Inc. All rights reserved.

A (δ, g)-cage is a regular graph of degree δ and girth g with the least possible number of vertices. Recently, some authors have addressed the problem of studying their connectivity parameters. In this direction, it was conjectured by Fu, Huang and Rodger that every (δ, g)-cage is maximally connected, i.e., it is δ-connected, and they proved this statement for δ = 3. We provide a new contributi...

The effect of activation and overexpression of the nuclear receptor PPAR-β/δ in human MDA-MB-231 (estrogen receptor-negative; ER(-)) and MCF7 (estrogen-receptor-positive; ER(+)) breast cancer cell lines was examined. Target gene induction by ligand activation of PPAR-β/δ was increased by overexpression of PPAR-β/δ compared with controls. Overexpression of PPAR-β/δ caused a decrease in cell prol...

Spatial variation in marine oxygen isotope ratios (δ (18)O) resulting from differential evaporation rates and precipitation inputs is potentially useful for characterizing marine mammal distributions and tracking movements across δ (18)O gradients. Dentine hydroxyapatite contains carbonate and phosphate that precipitate in oxygen isotopic equilibrium with body water, which in odontocetes closel...