• Combinatorics of oriented trees and tree-like structures 

      Isaac Owino Okoth (Stellenbosch University, 2015)
      In this thesis, a number of combinatorial objects are enumerated. Du and Yin as well as Shin and Zeng (by a different approach) proved an elegant formula for the number of labelled trees with respect to a given ...
    • Combinatorics of oriented trees and tree-like structures 

      Isaac Owino Okoth (Stellenbosch University, 2015)
      In this thesis, a number of combinatorial objects are enumerated. Du and Yin as well as Shin and Zeng (by a different approach) proved an elegant formula for the number of labelled trees with respect to a given in degree ...
    • On Noncrossing and Plane Tree-Like Structures 

      Isaac Owino Okoth (Communications in Advanced Mathematical Sciences, 2021)
      Mathematical trees are connected graphs without cycles, loops and multiple edges. Various trees such as Cayley trees, plane trees, binary trees, d-ary trees, noncrossing trees among others have been studied extensively. ...
    • Refined enumeration of 2-noncrossing trees 

      Isaac Owino Okoth (Academic Publishing House, 2021)
      A 2-noncrossing tree is a connected graph without cycles that can be drawn in the plane with its vertices on the boundary of circle such that the edges are straight line segments that do not cross and all the vertices ...