Tsend-Ayush Selenge- Doctor of Philosophy
- Professor (Associate) at National University of Mongolia
Tsend-Ayush Selenge
- Doctor of Philosophy
- Professor (Associate) at National University of Mongolia
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10
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Publications (10)
Introduction/purpose: Degree-based graph invariants are a type of molecular descriptor that represent the connectivity of atoms (vertices) in a molecule through bonds (edges). They are used to model structural properties of molecules and provide valuable information for fields such as physical chemistry, pharmacology, environmental science, and mat...
The graph invariant RM2, known under the name reduced second Zagreb index, is defined as (Formula presented), where dG(v) is the degree of the vertex v of the graph G. In this paper, we give a tight upper bound of RM2 for the class of graphs of order n and size m with at least one dominating vertex. Also, we obtain sharp upper bounds on RM2 for all...
Given a graph G = (V, E), the variable first and second Zagreb indices are defined by λ M 1 (G) = vi∈V d 2λ i and λ M 2 (G) = vivj ∈E d λ i · d λ j , where d i is the degree of the vertex v i and λ is any real number. Let G ν be the class of connected graphs with cyclomatic number ν (ν ≥ 1). In this paper, we give a lower bound on λ M 2 (G) − λ M 1...
Let G=(V,E) be a graph with vertex set V and edge set E. The ve-degree of a vertex v∈V equals the number of edges ve-dominated by v and the ev-degree of an edge e∈E equals the number of vertices ev-dominated by e. Recently, Chellali et al. studied the properties of ve-degree and ev-degree of graphs (Chellali et al., 2017). Also they focused on the...
The classical first and second Zagreb indices of a graph are defined as and , where is the degree of the vertex of graph . Recently, Furtula et al. (2014) studied the difference between the Zagreb indices and mentioned a problem to characterize the graphs for which or or . In this paper we completely solve this problem.
Discontinuous-continuous Galerkin methods approximate the solution to a population diffusion model with finite life span. The regularity of the solution depends on mortality; it decreases when mortality is high enough. The numerical solution has strong stability and a priori error estimates are obtained away from the region where the solution is no...
The first and second Zagreb indices of a graph G are defined as M_1(G)={\sum}_{{\nu}{\in}V}d_G({\nu})^2 and M_2(G)={\sum}_{u{\nu}{\in}E(G)}d_G(u)d_G({\nu}). where d_G({\nu}) is the degree of the vertex {\nu}. G is called a k-apex tree if k is the smallest integer for which there exists a subset X of V (G) such that {\mid}X{\mid} = k and G-X is a tr...
Continuous Galerkin finite element methods in the age-time domain are proposed to approximate the solution to the model of population dynamics with unbounded mortality (coefficient) function. Stability of the method is established and a priori L2L2-error estimates are obtained. Treatment of the nonlocal boundary condition is straightforward in this...
The Lotka-McKendrick model which describes the evolution of a single population is developed from the well known Malthus model. In this paper, we introduce the Lotka-McKendrick model. We approximate the solution to the model using hp-discontinuous Galerkin finite element method. The numerical results show that the presented hp-discontinuous Galerki...
The Lotka-McKendrick equation which describes the evolution of a single population under the phenomenological conditions is developed from the well-known Malthus’model. In this paper, we introduce the Lotka-McKendrick equation for the description of the dynamics of a population. We apply a discontinuous Galerkin finite element method in age-time do...
