African Journal of
Mathematics and Computer Science Research

  • Abbreviation: Afr. J. Math. Comput. Sci. Res.
  • Language: English
  • ISSN: 2006-9731
  • DOI: 10.5897/AJMCSR
  • Start Year: 2008
  • Published Articles: 257

Table of Content: 15 September 2011; 4(10)

September 2011

Characterization of de Bruijn graphs homomorphisms

  We study homomorphisms between de Bruijn digraphs of different orders. A main theme of this paper is to characterize de Bruijn graph homomorphisms such that the inverse of a factor in the lower order digraph is also a factor in the higher order one, where a factor is a collection of cycles that partition the digraph. We generalize Lempel's homomorphism by describing and characterizing a class of...

Author(s): Akinwande Mufutau Babatunde O.

September 2011

On weakly symmetric and weakly Ricci symmetric Lorentzian Para-Sasakian manifolds

  The aim of the present paper is to study weakly symmetric and weakly Ricci symmetric an LP-Sasakian manifolds and proved that if weakly symmetric LP-Sasakian manifold satisfies -parallel Ricci condition then the scalar curvature of the manifolds is equal to rank of . If weakly symmetric an LP-Sasakian manifolds satisfies Ricci tensor of coddazi type then the manifolds is R-Harmonic, further we have...

Author(s): Dhruwa Narain and Sunil Yadav

September 2011

Conceptual networks: The role of concept lattices in knowledge management

Concepts are defined as couples (O, A) of sets O and A: the object O (a set of none, or one or more elements) is assigned to the set A of these elements’ (common) attributes. The objects change according to the sequence of attributes. Only couples of objects and attributes, that is concepts, are adequate for our world. The connections and links we need in databases and multimedia are expressed, naturally, by...

Author(s):   Megaklis Th. Sotiropoulos

September 2011

Optimality of the flexible job shop scheduling problem

  The flexible job shop scheduling problem is NP-hard problem. There is no efficient technique to check the optimality of the solution of the flexible job shop scheduling problem. So, in this paper, theorems and lemmas for defining some optimality conditions for the solution of the flexible job shop scheduling problem are introduced. In addition, a mathematical model of the primal problem of the flexible job...

Author(s): Abd Elazeem Mohamed Abd Elazeem, Mohamed Sayed Ali Osman and Mohamed Bayoumi Ali Hassan

September 2011

Interpolation by quartic splines

  This paper proposes two special lacunary interpolation problems using quartic splines of continuity class C2. We call the problems (0,3) and (0,4) lacunary interpolation. In these two cases, the third and fourth derivative respectively is also prescribed in between the nodes along with the function value at the nodes. This paper is divided into two parts namely cases A and B. Case A deals with the (0,3)...

Author(s): Kulbhushan Singh

September 2011

Thermal stresses induced by a point heat source in a hollow disk by quasi-static approach

  This paper deals with the two dimensional non-homogeneous boundary value problem of heat conduction in a hollow disk defined as  and discussed the thermoelastic behavior due to internal heat generation within it. A thin hollow disk is considered having arbitrary initial temperature and subjected to time dependent heat flux at the outer circular boundary  whereas inner circular...

Author(s): K. C. Deshmukh, Y. I. Quazi and S. D. Warbhe