فهرست مطالب
Mathematics Interdisciplinary Research
Volume:6 Issue: 3, Summer 2021
- تاریخ انتشار: 1401/02/13
- تعداد عناوین: 6
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Pages 171-183A Sturm-Liouville problem with n-potential functions in the second order differential equation and which contains spectral parameter depending on linearly in one boundary condition is considered. The asymptotic formulas for the eigenvalues, nodal parameters (nodal points and nodal lengths) of this problem are calculated by the Prüfer's substitutions. Also, using these asymptotic formulas, an explicit formula for the potential functions are given. Finally, a numerical example is given.Keywords: Eigenvalues, Eigenfunctions, Prüfer's Substitutions, Sturm-Liouville problem, Inverse Nodal problem
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Pages 185-194The fixed point theorem of Nadler (1966) was extended by Mizoguchi and Takahashi in 1989 and then for multi-valued contraction mappings, the existence of fixed point was demonstrated by Daffer and Kaneko (1995). Their results generalized the Nadler’s theorem. In 2009 Kamran generalized Mizoguchi-Takahashi’s theorem. His theorem improve Klim and Wadowski results (2007), and extended Hicks and Rhoades (1979) fixed point theorem. Recently Rouhani and Moradi (2010) generalized Daffer and Kaneko’s results for two mappings. The results of the current work, extend the previous results given by Kamram (2009), as well as by Rouhani and Moradi (2010), Nadler (1969), Daffer and Kaneko (1995), and Mizoguchi and Takahashi (1986) for tow multi-valued mappings. We also give a positive answer to the Rouhani-Moradi’s open problem.Keywords: fixed point, Mizoguchi-Takahashi fixed point theorem, multi-valued mapping, weak contraction
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Pages 195-214In this paper, we study a delayed three-cell network which is introduced by coupled cell theory and neural network theory. We investigate this model with two different discrete delays. The aim is to obtain necessary conditions for the stability and the existence of Hopf-zero bifurcation in this model. Moreover, we find the normal form of this bifurcation by using linearization and the Multiple Time Scale method. Finally, the theoretical results are verified by numerical simulations.Keywords: Coupled cell theory, neural network, Stability, Hopf-zero bifurcation, Normal form
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Pages 215-223In this paper, by applying analytic combinatorics, we obtain an asymptotics for the t-th moment of the number of phrases of length l in the Lempel-Ziv parsing algorithms built over a string generated by an asymmetric Bernoulli model. We show that the t-th moment is approximated by its Poisson transform.Keywords: Lempel-Ziv parsing algorithm, phrases, digital search tree, moment
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Pages 225-234We obtain the exact relations of the Hosoya index that is defined as the sum of the number of all the matching sets, on some classes of cycle-related graphs. Moreover, this index of three graph families, namely, chain triangular cactus, Dutch windmill graph, and Barbell graph is determined.Keywords: Hosoya Index, Helm graph, graph lotus, chain triangular cactus, Dutch windmill graph
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Pages 235-242The subject of this paper is to study distribution of the prime factors p and their exponents, which we denote by vp (n!), in standard factorization of n! into primes. We show that for each θ > 0 the primes p not exceeding nθ eventually assume almost all value of the sum ∑p⩽nθ vp(n!). Also, we introduce the notion of θ-truncated factorial, defined by n!θ =∏p⩽nθ pvp (n!) and we show that the growth of log n!1/2 is almost half of growth of log n!1.Keywords: Factorial, Growth of arithmetic functions, Prime number