A new approximation formalism is applied to study the bound states of the Hellmann potential, which represents the superposition of the attractive Coulomb potential −a/r and the Yukawa potential b exp(−δr)/r of arbitrary strength b and screening parameter δ. Although the analytic expressions for the energy eigenvalues En,l yield quite accurate results for a wide range of n, l in the limit of ve...

In this paper we consider routing with compact tables in reliability networks. More precisely, we study interval routing on random graphs B p obtained from a base graph B by independently destroying each edge of B with a failure probability 1 p. We focus on additive stretched routing for n-node random graphs for which the base B is a square mesh and with p 0 5, that is the percolation model at ...

We define a new type of spectrum, called δ-approximate spectrum, of an element a in a complex unital Banach algebra A and show that the δ-approximate spectrum σ_δ (a) of a is compact. The relation between the δ-approximate spectrum and the usual spectrum is investigated. Also an analogue of the classical Gleason-Kahane-Zelazko theorem is established: For each ε>0, there is δ>0 such that if ϕ is...

Many graph drawing applications entail geographical constraints on positions of vertices; these constraints can be at odds with aesthetic requirements such as the use of straight-line edges or the number of crossings. Without positional constraints on vertices, of course, every planar graph can be drawn crossing-free with straight-line edges. On the other hand, inflexible and precise specificat...

The observed strong phase difference of 30 o between I = 3 2 and I = 1 2 final states for the decay B → Dπ is analyzed in terms of rescattering like D * π → Dπ, etc. It is concluded that for the decay B o → D + π − the strong phase is only about 10 o. Implications for the determination of sin (2β + γ) are discussed. The weak decay amplitude to a specific final state can be written as Ae iδ wher...

We present a study of the fiber bundle model using equal load-sharing dynamics where the breaking thresholds of the fibers are drawn randomly from a power-law distribution of the form p(b)∼b-1 in the range 10-β to 10β. Tuning the value of β continuously over a wide range, the critical behavior of the fiber bundle has been studied both analytically as well as numerically. Our results are: (i) Th...

There is a quadratic-time algorithm that determines conjugacy between finite subsets in any torsion-free hyperbolic group. Moreover, in any k-generator, δ-hyperbolic group Γ, if two finite subsets A and B are conjugate, then x−1Ax = B for some x ∈ Γ with ‖x‖ less than a linear function of max{‖γ‖ : γ ∈ A∪B}. (The coefficients of this linear function depend only on k and δ.) These results have i...

As an application of the method used to obtain the result above, we will obtain the consistency of b = ω1 < s = κ where b is the bounding number, s is the splitting number and κ is an arbitrary regular cardinal. Suppose ν ≥ δ. Begin with a model of GCH and adjoin δ-many Cohen reals 〈rα : α ∈ δ〉 followed by ν-many Random reals 〈sξ : ξ ∈ ν〉. That is, if Vδ is the model obtained after the first δ ...

In this paper we continue our investigation concerning the hyperbolic geometry on the noncommutative ball [B(H)]−1 := n (X1, . . . ,Xn) ∈ B(H) n : ‖X1X ∗ 1 + · · ·+XnX ∗ n‖ 1/2 ≤ 1 o , where B(H) is the algebra of all bounded linear operators on a Hilbert space H, and its implications to noncommutative function theory. The central object is an intertwining operator LB,A of the minimal isometric...

and Applied Analysis 3 Generalized derivations first appeared in the context of operator algebras 7 . Later, these were introduced in the framework of pure algebra 8, 9 . Definition 1.1. LetA be an algebra and let X be anA-bimodule. A linear mapping d : A → X is called i derivation if d ab d a b ad b , for all a, b ∈ A; ii generalized derivation if there exists a derivation in the usual sense δ...