• Positivity: N(v) ≥ 0 with equality if and only if v = 0. • Positive Homogeneity: N(αv) = |α|N(v). • Triangle Inequality: N(x1 + x2) ≤ N(x1) +N(x2). If N is a norm for V then we call ρ N (x1, x2) := N(x1−x2) the associated distance function (or metric) for V . A vector space V together with some a choice of norm is called a normed space, and the norm is usually denoted by ‖ ‖. If V is complete...

In this paper, we study the Diophantine equation x2 + C = 2yn in positive integers x, y with gcd(x, y) = 1, where n ≥ 3 and C is a positive integer. If C ≡ 1 (mod 4) we give a very sharp bound for prime values of the exponent n; our main tool here is the result on existence of primitive divisors in Lehmer sequence due Bilu, Hanrot and Voutier. When C 6≡ 1 (mod 4) we explain how the equation can...

Refining some results of S. S. Dragomir, several new reverses of the generalized triangle inequality in inner product spaces are given. Among several results, we establish some reverses for the Schwarz inequality. In particular, it is proved that if a is a unit vector in a real or complex inner product space (H; 〈., .〉), r, s > 0, p ∈ (0, s],D = {x ∈ H, ‖rx− sa‖ ≤ p}, x1, x2 ∈ D − {0} and αr,s ...

gp(X) = {x1 x2 2 . . . x n n | xi ∈ X, i = ±1} Définition 1.1. Soit X un ensemble. Un produit (ou suite) w = x1 x2 2 . . . x n n , | xi ∈ X, i = ±1 s’appelle un X–mot (ou mot) de longueur n. Si on considère les xi comme des éléments du groupe G, ce mot a une valeur g dans G, et nous écrivons x1 x2 2 . . . x n n =G g (certains écrivent w). Définition 1.2. On dit que le X–mot w = x1 x2 2 . . . x ...

A logic function f has a disjoint bi-decomposition i f can be represented as f = h(g1(X1); g2(X2)), where X1 and X2 are disjoint set of variables, and h is an arbitrary two-variable logic fuction. f has a non-disjoint bidecomposition i f can be represented as f(X1;X2; x) = h(g1(X1; x); g2(X2; x)), where x is the common variable. In this paper, we show a fast method to nd bidecompositions. Also,...

We begin with an intuitive description of the kind of operators we wish to study. The most general set-up is as follows: let M1 and M2 be manifolds of dimension n1 and n2, respectively and 1 ≤ k < n1. Suppose there exists a pair of smooth assignments x2 7→ γx2 and x2 7→ dσx2 , the former attaching a k-dimensional submanifold γx2 ⊂ M1 and the latter a smooth measure dσx2 on γx2 to each point x2 ...