2022-05-20T15:09:54Z https://mir.kashanu.ac.ir/?_action=export&rf=summon&issue=15269
2021-03-01 10.22052
Mathematics Interdisciplinary Research Math. Interdisc. Res. 2538-3639 2538-3639 2021 6 1 Gordon-Scantlebury and Platt Indices of Random Plane-oriented Recursive Trees Ramin Kazemi ‎For a simple graph G‎, ‎the Gordon-Scantlebury index of G is equal to the number of paths of length two in G‎, ‎and the Platt index is equal to the total sum of the degrees of all edges in G‎. ‎In this paper‎, ‎we study these indices in random plane-oriented recursive trees through a recurrence equation for the first Zagreb index‎. ‎As n ∊ ∞, ‎the asymptotic normality of these indices are given‎. Gordon-Scantlebury index‎ ‎Platt index‎ ‎the first Zagreb index‎ plane-oriented recursive tree‎ ‎asymptotic normality 2021 03 01 1 10 https://mir.kashanu.ac.ir/article_110787_44ba1fd905ac99274f659196098a164d.pdf
2021-03-01 10.22052
Mathematics Interdisciplinary Research Math. Interdisc. Res. 2538-3639 2538-3639 2021 6 1 DE Sinc-Collocation Method for Solving a Class of Second-Order Nonlinear BVPs Ali Eftekhari Abbas Saadatmandi In this work, we develop the Sinc-collocation method coupled with a Double exponential transformation for solving a special class of nonlinear second-order multi-point boundary value problems (MBVP). This method attains a convergence rate of exponential order. Four numerical examples are also examined to demonstrate the efficiency and functionality of the newly proposed approach. Double Exponential transformation Collocation points Multi-point boundary value problem Sinc methods 2021 03 01 11 22 https://mir.kashanu.ac.ir/article_107701_d8d78cde3127e17364f9e1b9d0b67eff.pdf
2021-03-01 10.22052
Mathematics Interdisciplinary Research Math. Interdisc. Res. 2538-3639 2538-3639 2021 6 1 Adjointness of Suspension and Shape Path Functors Tayyebe Nasri Behrooz Mashayekhy Hanieh Mirebrahimi In this paper, we introduce a subcategory ∼Sh* of Sh* and obtain some results in this subcategory. First we show that there is a natural bijection Sh(∑(X, x), (Y,y))≅Sh((X,x),Sh((I, Ī),(Y,y))), for every (Y,y)∈ ~Sh* and (X,x)∈ Sh*. By this fact, we prove that for any pointed topological space (X,x) in ∼Sh*,πntop(X,x)≅ πn-ktop(Sh((Sk, *),(X,x)), ex), for all 1≤k ≤n-1. Shape category Topological shape homotopy group Shape group Suspensions 2021 03 01 23 33 https://mir.kashanu.ac.ir/article_111348_a639434f373b5e2c1e63558d731d8772.pdf
2021-03-01 10.22052
Mathematics Interdisciplinary Research Math. Interdisc. Res. 2538-3639 2538-3639 2021 6 1 Schwinger Pair Creation by a Time-Dependent Electric Field in de Sitter Space with the Energy Density E_μ E^μ=E^2 a^2(τ) Fatemeh Monemi Farhad Zamani We investigate Schwinger pair creation of charged scalar particles from a time-dependent electric field background in (1+3)-dimensional de Sitter spacetime. Since the field's equation of motion has no exact analytical solution, we employ \emph{Olver's uniform asymptotic approximation method} to find its analytical approximate solutions. Depending on the value of the electric field E, and the particle's mass m, and wave vector k, the equation of motion has two turning points, whose different natures (real, complex, or double) lead to different pair production probability. More precisely, we find that for the turning points to be real and single, m and k should be small, and the more smaller are the easier to create the particles. On the other hand, when m or k is large enough, both turning points are complex, and the pair creation is exponentially suppressed. In addition, we study the pair creation in the weak electric field limit, and find that the semi-classical electric current responds as E1-2√μ², where μ²=(9/4)-(m2ds/ H2). Thus, below a critical mass mcr=√2 H, the current exhibits the infrared hyperconductivity. Schwinger mechanism electromagnetic processes time-dependent electric field uniform asymptotic approximation 2021 03 01 35 61 https://mir.kashanu.ac.ir/article_111349_ca34fec44c952148702bac12fa527227.pdf
2021-03-01 10.22052
Mathematics Interdisciplinary Research Math. Interdisc. Res. 2538-3639 2538-3639 2021 6 1 Auto-Engel Polygroups Ali Mosayebi-Dorcheh Mohammad Hamidi Reza Ameri This paper introduces the concept of auto–Engel polygroups via the heart of hypergroups and investigates the relation between of auto–Engel polygroups and auto–nilpotent polygroups. Indeed, we show that the concept of heart of hypergroups plays an important role on construction of auto–Engel polygroups. This study considers the notation of characteristic set in hypergroups with respect to automorphism of hypergroups and shows that the heart of hypergroups is a characteristic set in hypergroups. Auto–Engel polygroup characteristic(-closure) set general fundamental relation 2021 03 01 63 83 https://mir.kashanu.ac.ir/article_111522_26aefb3680a000cee94cf14b3e61aabc.pdf
2021-03-01 10.22052
Mathematics Interdisciplinary Research Math. Interdisc. Res. 2538-3639 2538-3639 2021 6 1 On n-A-con-cos Groups and Determination of some 3-A-con-cos Groups Ahmad Gholami Fatemeh Mahmudi In this paper, we introduce the concept of n-A-con-cos groups, n ≥ 2, mention some properties of them and determine all finite abelian groups with at most two direct factors. As a consequence, it is proved that dihedral groups D2m in which m has at most two prime factors are n-A-con-cos. n th−autocommutator subgroup finite abelian groups dihedral groups n-A-con-cos groups 2021 03 01 85 95 https://mir.kashanu.ac.ir/article_102140_501ddd5549ad4d06d5b489e8d7ef1a0b.pdf