Browsing Research Articles (Mathematics and Applied Mathematics) by Title

Browsing Research Articles (Mathematics and Applied Mathematics) by Title

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  • Relative congruence formulas and decompositions in quasivarieties 
    Campercholi, M.A.; Raftery, James G. (Springer, 2017-11)
    Quasivarietal analogues of uniform congruence schemes are discussed, and their relationship with the equational definability of principal relative congruences (EDPRC) is established, along with their significance for ...
  • Relative discrete spectrum of W*-dynamical system 
    Duvenhage, Rocco de Villiers; King, Malcolm (Springer, 2021-01)
    A definition of relative discrete spectrum of noncommutative W*-dynamical systems is given in terms of the basic construction of von Neumann algebras, motivated from three perspectives: First, as a complementary concept ...
  • Relative weak mixing of W∗-dynamical systems via joinings 
    Duvenhage, Rocco de Villiers; King, Malcolm (Polish Academy of Sciences, Institute of Mathematics, 2019)
    A characterization of relative weak mixing in W∗-dynamical systems in terms of a relatively independent joining is proven.
  • Reliable finite element methods for self-adjoint singular perturbation problems 
    Lubuma, Jean M.-S.; Patidar, Kailash C. (NISC, 2009)
    It is well known that the standard finite element method based on the space Vh of continuous piecewise linear functions is not reliable in solving singular perturbation problems. It is also known that the solution of a ...
  • Reliable numerical schemes for a linear difusion equation on a nonsmooth domain 
    Chin, P.W.M. (Pius Wiysanyuy Molo); Djoko, J.K. (Jules Kamdem); Lubuma, Jean M.-S. (Elsevier, 2010-05)
    The solution of a linear reaction–diffusion equation on a non-convex polygon is proved to be globally regular in a suitable weighted Sobolev space. This result is used to design an optimally convergent Fourier-Finite Element ...
  • Resonance, stability and period-doubling bifurcation of a quarter-car model excited by the road surface profile 
    Siewe, M. Siewe (Elsevier, 2010)
    Stability and the steady states of the transverse motion of a quarter-car model excited by the road surface profile with non-symmetric potential is investigated. Initially, a set of slow-flow equations is derived using the ...
  • Review of a predator-prey model with two limit cycles 
    Van der Hoff, Quay; Harding, Ansie (Taylor and Francis, 2018)
    It is well-known that the Lotka–Volterra predator-prey model has a family of periodic orbits, but does not possess limit cycles and therefore the model is said to be structurally unstable. The Lotka–Volterra model is a ...
  • Risk-based optimal portfolio of an insurance firm with regime switching and noisy memory 
    Guambe, Calisto; Kufakunesu, Rodwell; Mabitsela, Lesedi (American Institute of Mathematical Sciences, 2024)
    Please read abstract in the article.
  • RNP and Lewis RNP for all 14 natural tensor norms of Grothendieck 
    Maepa, S.M. (Salthiel Malesela) (NISC, 2011)
    We classify all 14 natural tensor norms of Grothendieck according to the possession of the lack of the Radon-Nikodym property (RNP) and the Lewis Radon-Nikodym property.
  • A robust spectral integral method for solving chaotic finance systems 
    Moutsinga, Claude Rodrigue Bambe; Pindza, Edson; Mare, Eben (Elsevier, 2020-03)
    Nonlinear chaotic finance systems are represented by nonlinear ordinary differential equations and play a significant role in micro-and macroeconomics. In general, these systems do not have exact solutions. As a result, ...
  • The Ross recovery theorem with a regularised multivariate Markov chain 
    Van Appel, Vaughan; Mare, Eben (Operations Research Society of South Africa, 2018-11-04)
    Recently, Ross derived a theorem, namely the “Recovery Theorem”, that allows for the recovery of the pricing kernel and real-world asset distribution, under particular assumptions, from a forward-looking risk neutral ...
  • Safe spending rates for South African retirees 
    Mare, Eben (AOSIS Open Journals, 2016-01)
    Retirees face a difficult financial choice. They need to decide on an appropriate amount to withdraw from their retirement investment and they need to ‘optimise’ between outliving their money and living below their means. ...
  • Semilinear De Morgan monoids and epimorphisms 
    Wannenburg, Johann Joubert; Raftery, James G. (Springer, 2024-01)
    A representation theorem is proved for De Morgan monoids that are (i) semilinear, i.e., subdirect products of totally ordered algebras, and (ii) negatively generated, i.e., generated by lower bounds of the neutral element. ...
  • Sex-structured model of Wolbachia invasion and design of sex-biased release strategies in Aedes spp mosquitoes populations 
    Bliman, Pierre-Alexandre; Dumont, Yves; Escobar-Lasso, Oscar Eduardo; Martinez-Romero, Hector J.; Vasilieva, Olga (Elsevier, 2023-07)
    Laboratory experiments as well as some field essays have revealed that the intracellular bacterium Wolbachia, deliberately introduced in Aedes spp female mosquitoes, drastically reduces their vector competence for dengue ...
  • Shear flows of a new class of power-law fluids 
    Le Roux, Christiaan; Rajagopal, Kumbakonam R. (Springer, 2013-02)
    We consider the flow of a class of incompressible fluids which are constitutively defined by the symmetric part of the velocity gradient being a function, which can be nonmonotone, of the deviator of the stress tensor. ...
  • Sibling curves and complex roots 2 : looking ahead 
    Harding, Ansie; Engelbrecht, Johann (Taylor & Francis, 2007-01-07)
    This paper, the second of a two part article, expands on an idea that appeared in literature in the 1950s to show that by resticting the domain to those complex numbers that map onto real numbers, representations of functions ...
  • Sibling curves of cubic polynomials 
    Wiggins, Harry (NISC (Pty) Ltd and Informa UK Limited (trading as the Taylor & Francis Group), 2020)
    Sibling curves are a new way to represent the zeroes of any complex-valued function. Interesting results are already known for the sibling curves of quadratic polynomials. In this article a complete investigation of sibling ...
  • A simple mathematical model for Ebola in Africa 
    Tsanou, Berge; Lubuma, Jean M.-S.; Moremedi, G.M.; Morris, Neil Kenneth; Kondera-Shava, R. (Taylor and Francis, 2017)
    We deal with the following question: Can the consumption of contaminated bush meat, the funeral practices and the environmental contamination explain the recurrence and persistence of Ebola virus disease outbreaks in Africa? ...
  • A simulation study to assess the epidemiological impact of pneumonia transmission dynamics in high-risk populations 
    Chukwu, C.W.; Tchoumi, Stephane Y.; Diagne, M.L. (Elsevier, 2024-03)
    The term “high-risk population” refers to individuals with an increased likelihood of contracting a severe illness or disease due to factors such as age, underlying medical conditions, pregnancy, geographical location, or ...
  • Simultaneous identification of damping coefficient and initial value for PDEs from boundary measurement 
    Zhao, Zhi-Xue; Banda, M.K. (Mapundi); Guo, Bao-Zhu (Taylor and Francis, 2018)
    In this paper, simultaneous identification of damping or anti-damping coefficient and initial value for some Riesz spectral systems is considered. An identification algorithm is proposed based on the fact that the output ...