Department of Mathematics: Recent submissions

Now showing items 1-20 of 73

    • Counting formulas and bijections of nondecreasing 2-noncrossing trees 

      Kariuki, Yvonne Wakuthii; Okoth, Isaac Owino; Nyamwala, Fredrick Oluoch (Electronic Journal of Mathematics, 2024-07-02)
      In this paper, we introduce nondecreasing 2-noncrossing trees and enumerate them according to their number of vertices, root degree, and number of forests. We also introduce nondecreasing 2-noncrossing increasing trees ...

    • Enumeration of k-plane trees and forests 

      Nyariaro, Albert Oloo; Okoth, Isaac Owino (Ghaem Technology Institute of Higher Education, 2024-08-18)
      A k-plane tree is an ordered tree in which the vertices are labelled by integers {1, 2, . . . , k} and satisfies the condition i + j ⩽ k + 1 where i and j are adjacent vertices in the tree. These trees are known to be ...

    • On non-decreasing 2-plane trees 

      Kariuki, Yvonne Wakuthii; Okoth, Isaac Owino; Nyamwala, Fredrick Oluoch (Ghaem Technology Institute of Higher Education, 2024-08-08)
      In this paper, we have introduced the set of non-decreasing 2-plane trees. These are plane trees whose vertices receive labels from the set {1, 2} such that the sum of labels of adjacent vertices is at most 3 and that the ...

    • Bijections for classes of labelled trees. 

      Nyariaro, Albert Oloo; Okoth, Isaac Owino (University of Isfahan, 2024-09-01)
      Trees are acyclic connected graphs. Plane trees, d-ary trees, binary trees, noncrossing trees and their generalizations, which are families of trees, have been enumerated by many authors using various statistics. These ...

    • Bijections of plane Husimi graphs and certain combinatorial structures 

      Kariuki, Yvonne Wakuthii (EU Academic Publishers, 2023-10-19)
      Plane Husimi graphs are combinatorial structures obtained when we replace edges in plane trees with complete graphs such that the resultant structures are connected and cycle free. The formula that counts these structures ...

    • Bijections for classes of labelled trees 

      Nyariaro, Albert P. Oloo; Okoth, Isaac .Owino (University of Isfahan, 2024-01-09)
      Trees are acyclic connected graphs. Plane trees, d-ary trees, binary trees, non crossing trees and their generalizations, which are families of trees, have been enumerated by many authors using various statistics. These ...

    • Enumeration of plane and d-ary tree-like structures 

      Onyango, Christopher Amolo; Okoth, Isaac Owino; Kasyoki, Donnie Munyao (Annals of Mathematics and Computer Science, 2023-08-26)
      Trees are generalized using various approaches such as considering tree-like structures. Some of the tree-like structures are Husimi graphs, cacti and oriented cacti. These graphs have been enumerated according to number ...

    • Reachability in complete t-ary trees 

      Abayo, Sylvester Arthur; Okoth, Isaac Owino; Kasyoki, Donnie Munyao (Annals of Mathematics and Computer Science, 2023-10-01)
      Mathematical trees such as Cayley trees, plane trees, binary trees, noncrossing trees, t-ary trees among others have been studied extensively. Reachability of vertices as a statistic has been studied in Cayley trees, plane ...

    • On the Numerical Solution of Boundary Value Problem (BVP) of the Ordinary Differential Equation (ODE) - The Case of Steady-State Bio-Heat Equation with Combined Heat Transfer Coefficient by Pseudo-Spectral Collocation Method 

      Odongo, Benard A; Manyonge, Alfred W; Owego, Dancun O; Opiyo, Richard O (European Journal of Engineering and Technology Research, 2023-09-15)
      Spectral methods for the solution of a boundary value problem of an ordinary differential equation are reviewed with particular emphasis laid on pseudo-spectral collocation method. The pseudo-collocation method is then ...

    • Bijections of k-plane trees 

      Owino, Isaac. Okoth (Open journal of discrete Applied Mathematics, 2022)
      A k-plane tree is a tree drawn in the plane such that the vertices are labeled by integers in the set {1, 2, . . . , k}, the children of all vertices are ordered, and if (i, j) is an edge in the tree, where i and j are ...

    • Refined enumeration of k-plane trees and k-noncrossing trees 

      Isaac Owino Okoth, Stephan Wagner (2022)
      A k-plane tree is a plane tree whose vertices are assigned labels between 1 and k in such a way that the sum of the labels along any edge is no greater than k+1. These trees are known to be related to (k+1)-ary trees, and ...

    • Application of binary logistic regression model: determinants of contraceptive utilization. 

      Caleb Okeyo Oyala (IJRAR, 2020)
      Contraceptives uptake among the youth has been a sensitive and controversial issue in the society that has resulted to various social problems that include unwanted pregnancies and sexual transmitted infections among ...

    • Three Dimensional Mathematical Models for ConvectiveDispersive Flow of Pesticides in Porous Media 

      Seth H. W. Adams, Alfred Manyonge (IJESC, 2018)
      The transport of solutes through porous media where chemicals undergo adsorption or change process on the surface of the porous materials has been a subject of research over years. Usage of pesticides has resulted in ...

    • Norm Properties of S -Universal Operators 

      MUHOLO Joshua, BONYO,Job (Communications in Advanced Mathematical Sciences, 2020)
      We investigate the norm properties of a generalized derivation on a norm ideal J in B(H), the algebra of bounded linear operators on a Hilbert space H. Specifically, we extend the concept of S−universality from the inner ...

    • Spectra of Composition Groups on the Weighted Dirichlet Space of the Upper Half-Plane 

      M. O. Agwang & J. O. Bonyo (Springer, 2020)
      We prove that the group of weighted composition operators induced by contin uous automorphism groups of the upper half plane U is strongly continuous on the weighted Dirichlet space of U, Dα(U). Further, we investigate ...

    • On the Norm of a Generalized Derivation 

      Odero Adhiambo Beatrice, J. O. Agure,F. O. Nyamwala (HIKARI Ltd, 2019)
      Let H be an infinite dimensional complex Hilbert space and B(H) the algebra of all bounded linear operators on H. For two bounded operators A, B ∈ B(H), the map δAB : B(H) → B(H) is a generalized inner derivation operator ...

    • Farmer versus Researcher data collection methodologies: Understanding variations and associated trade-offs 

      Hannington Ochieng1, 2* , John Ojiem1 , Joyce Otieno2 (2019)
      The number of non-experts (such as farmers) participating in research activities has increased over the years, with the aim of them addressing their heterogeneous conditions. The situation has resulted in them being ...

    • Comparative Analysis of Spectral Theory of Second Order Difference and Differential Operators with Unbounded Odd Coefficient 

      Fredrick Oluoch Nyamwala, David Otieno Ambogo, Joyce Mukhwana Ngala (KYUNGPOOK, 2020)
      We show that selfadjoint operator extensions of minimal second order differ ence operators have only discrete spectrum when the odd order coefficient is unbounded but grows or decays according to specific conditions. ...

    • NOTIONS OF CONTINUITY FOR FINITE RANK MAPS IN THE SPACE OF NORMAL OPERATORS 

      J. A. OTIENO1 , D. O. AMBOGO, AND F. O. NYAMWALA (2020)
      We show that a natural extension of a continuous finite rank operator to an arbitrary Hilbert space is continuous. We also give sufficient conditions to calculate delta- epsilon numbers in all the domains of T. In addition, we ...

    • On some properties of generalized Fibonacci polynomials 

      Fidel Oduol (Open Journal of Discrete Applied Mathematics, 2020)
      Fibonacci polynomials have been generalized mainly by two ways: by maintaining the recurrence relation and varying the initial conditions and by varying the recurrence relation and maintaining the initial conditions. In ...