We formulate a linear difference equation which yields averaged semi-inclusive decay rates for arbitrary, not necessarily large, values of the masses. We show that the rates for decays M → m+M ′ of typical heavy open strings are independent of the masses M and m, and compute the “mass deffect” M−m−M ′. For closed strings we find decay rates proportional to Mm(1−D)/2 R , wheremR is the reduced m...

The main goal of the paper is to investigate boundedness, invariant intervals, semicycles, and global attractivity of all nonnegative solutions of the equation xn 1 α βxn γxn−k / 1 xn−k , n ∈ N0, where the parameters α, β, γ ∈ 0,∞ , k ≥ 2 is an integer, and the initial conditions x−k, . . . , x0 ∈ 0,∞ . It is shown that the unique positive equilibrium of the equation is globally asymptotically ...

In this note, we study the general form of some rational recursive sequences. By some modification of the methods and ideas, as well as the transformation from the paper [K. The global attractivity of the rational difference equation y n = y n−k +yn−m 1+y n−k yn−m , Appl. Math. Lett. 20 (2007), 54–58], we give a new proof for the conjectures posed therein.

whenever (un) ∞ n=0 is a non-degenerate linear recurrence sequence. Mahler’s proof is not effective in the following sense. Given a positive integer m the proof does not yield a number C(m) which is effectively computable in terms of m, such that |un| > m whenever n > C(m). However, Schmidt [31, 32], Allen [1], and Amoroso and Viada [2] have given estimates in terms of t only for the number of ...

The diversity of life is a fundamental empirical fact of nature. Casual observation alone confirms the great variety of species. But diversity also prevails within single species. As in human populations, the individuals of a species vary considerably in their outward traits—size and shape, external markings, fecundity, disease resistance, etc. This is called phenotypic variation, and, since ph...

We investigate how the behaviour, especially at 1; of continuous real solutions f (t) to the equation f (t) = a 1 f (t + h 1) + a 2 f (t ? h 2); where a 1 ; a 2 ; h 1 ; h 2 are positive real constants, depends on the values of these parameters. Deenitive answers are given, except in certain cases when h 1 =h 2 is rational..

We then define the Pfaffian transformation of (a0, a1, a2, ...) to be the sequence of Pfaffians (Pf(A0), P f(A1), P f(A2), ...), where the Pfaffian of a skew-symmetric matrix is the positive or negative square root of its determinant. (For a precise definition of the Pfaffian, see section 2.) The Pfaffian transformation is thus a function from sequences to sequences. We begin by observing the e...

The 321,hexagon–avoiding (321–hex) permutations were introduced and studied by Billey and Warrington in [4] as a class of elements of Sn whose Kazhdan– Lusztig and Poincaré polynomials and the singular loci of whose Schubert varieties have certain fairly simple and explicit descriptions. This paper provides a 7–term linear recurrence relation leading to an explicit enumeration of the 321–hex pe...

where the A{ are rational integers, is called an integral linear recurrence of order k. Given such a linear recurrence and an integer c, one would like to know for what n does f(n) — c? In a very few particular instances (e.g. see [2], [6]) this question has been answered, but in general the question is very difficult. A less exacting problem is the determination of upper and lower bounds on th...

In this paper we examine the application of temporal difference methods in learning a linear state value function approximation in a game of give-away checkers. Empirical results show that the TD(λ) algorithm can be successfully used to improve playing policy quality in this domain. Training games with strong and random opponents were considered. Results show that learning only on negative game...