Browsing Research Articles (Mathematics and Applied Mathematics) by Title

Browsing Research Articles (Mathematics and Applied Mathematics) by Title

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  • Value at risk in the South African equity market : a view from the tails 
    Milwidsky, C.; Mare, Eben (Juta, 2010-09)
    Traditional parametric Value at Risk (VaR) estimates assume normality in financial returns data. However, it is well known that this distribution, while convenient and simple to implement, underestimates the kurtosis ...
  • Vanishing elements and Sylow subgroups 
    Madanha, Sesuai Yasha (Taylor and Francis, 2022-07)
    Please read abstract in the article.
  • Variations and extensions of the Gaussian concentration inequality, Part I 
    Fresen, Daniel J. (Taylor and Francis, 2023)
    The classical Gaussian concentration inequality for Lipschitz functions is adapted to a setting where the classical assumptions (i.e. Lipschitz and Gaussian) are not met. The theory is more direct than much of the existing ...
  • Varieties of De Morgan monoids : covers of atoms 
    Moraschini, Tommaso; Raftery, James G.; Wannenburg, Johann Joubert (Cambridge University Press, 2020)
    The variety DMM of De Morgan monoids has just four minimal subvarieties. The join-irreducible covers of these atoms in the subvariety lattice of DMM are investigated. One of the two atoms consisting of idempotent algebras ...
  • Varieties of De Morgan monoids : minimality and irreducible algebras 
    Moraschini, Tommaso; Raftery, James G.; Wannenburg, Johann Joubert (Elsevier, 2019-07)
    Please read abstract in the article.
  • Vector semi-inner products 
    Rose, Kyle; Schwanke, Christopher Michael; Ward, Zachary (Mathematical Sciences Publishers, 2022-07)
    Please read abstract in the article.
  • Veralgemeende Sylvester-Gallai Stelling 
    Swanepoel, Konrad Johann; Pretorius, Lou M. (Lourens Martin) (Suid Afrikaanse Akademie vir Wetenskap & Kuns, 2007-03)
    Ons gee 'n algoritmiese bewys vir die kontrapositief van die volgende stelling wat onlangs deur die outeurs bewys is: Laat S 'n eindige versameling van punte in die vlak wees, met elke punt rooi, blou of met beide kleure ...
  • Vibration of a Reissner-Mindlin-Timoshenko plate-beam system 
    Labuschagne, A.; Van Rensburg, N.F.J.; Van der Merwe, A.J. (Elsevier, 2009)
    In this paper, we consider a plate-beam system in which the Reissner-Mindlin plate model is combined with the Timoshenko beam model. Natural frequencies and vibration modes for the system are calculated using the finite ...
  • Viscosity limit and deviations principles for a grade-two fluid driven by multiplicative noise 
    Razafimandimby, Paul Andre (Springer, 2018-03)
    Please read abstract in the article.
  • Volatility – ubiquitous, yet evasive? 
    Mare, Eben (Treasury Management International, 2014)
    In this article we discuss aspects of asset class volatility. We look specifically at the VIX index and some of its properties – VIX has become very popular in the media of late, especially with low historical levels being ...
  • Waves without the wave equation : examples from nonlinear acoustics 
    Dziwa, S.K. (Simba); Sauer, Niko (Elsevier, 2018-12)
    The traditional wave equation is mostly, if not always, obtained from a system of first order partial differential equations augmented by constitutive relations. These are often nonlinear and linearizations are forcibly ...
  • Weak solutions of a stochastic model for two-dimensional second grade fluids 
    Razafimandimby, Paul Andre; Sango, Mamadou (Hindawi Publishing Corporation, 2010)
    We initiate the investigation of a stochastic system of evolution partial differential equations modelling the turbulent flows of a second grade fluid filling a bounded domain of R2. We establish the global existence of ...
  • Weakly totally permutable products and fitting classes 
    Madanha, Sesuai Yasha (University of Isfahan, 2021-03)
    Please read abstract in the article.
  • Weather-driven malaria transmission model with gonotrophic and sporogonic cycles 
    Okuneye, Kamaldeen; Eikenberry, Steffen E.; Gumel, Abba B. (Taylor and Francis, 2019)
    Malaria is mainly a tropical disease and its transmission cycle is heavily influenced by environment: The life-cycles of the Anopheles mosquito vector and Plasmodium parasite are both strongly affected by ambient ...
  • What if quantum theory violates all mathematics? 
    Rosinger, Elemer E. (De Gruyter Open, 2017)
    It is shown by using a rather elementary argument in Mathematical Logic that if indeed, quantum theory does violate the famous Bell Inequalities, then quantum theory must inevitably also violate all valid mathematical ...
  • Why has the equal weight portfolio underperformed and what can we do about it? 
    Taljaard, Byran Hugo; Mare, Eben (Routledge, 2021)
    It is widely noted that market capitalisation weighted portfolios are inefficient and underperform an equal weighted portfolio over the long-term. However, at least since 2016, an equal weighted portfolio of stocks in the ...
  • Wiener index of trees of given order and diameter at most 6 
    Mukwembi, Simon; Vetrik, Tomas (Cambridge University Press, 2014-06)
    The long-standing open problem of nding an upper bound for the Wiener index of a graph in terms of its order and diameter is addressed. Sharp upper bounds are presented for the Wiener index, and the related degree ...
  • Will an imperfect vaccine curtail the COVID-19 pandemic in the U.S.? 
    Iboi, Enahoro A.; Ngonghala, Calistus N.; Gumel, Abba B. (KeAi Publishing Communications Ltd., 2020-08-06)
    The novel coronavirus (COVID-19) that emerged from Wuhan city of China in late December 2019 continue to pose devastating public health and economic challenges across the world. Although the community-wide implementation ...
  • Will vaccine-derived protective immunity curtail COVID-19 variants in the US? 
    Mancuso, Marina; Eikenberry, Steffen E.; Gumel, Abba B. (KeAi Communications, 2021-09-09)
    Multiple effective vaccines are currently being deployed to combat the COVID-19 pandemic, and are viewed as the major factor in marked reductions of disease burden in regions with moderate to high vaccination coverage. ...
  • Wiskundige modellering : vanaf skool na universiteit 
    Harding, Ansie (Suid Afrikaanse Akademie vir Wetenskap & Kuns, 2009-12)
    The outcomes based education (OBE) system is characterised by controversy and the 2008 matric results that rendered admission to an unusually large number of students did nothing to silence critics. The first students ...