Now showing items 26-42 of 42

    • A new characterization of periodic oscillations in periodic difference equations 

      Al-Salman, Ahmad; Al-Sharawi, Ziyad (Elsevier, 2011-11)
      In this paper, we characterize periodic solutions of p-periodic difference equations. We classify the periods into multiples of p and nonmultiples of p. We show that the elements of the set of multiples of p follow the ...
    • On phi-Dedekind rings and phi-Krull rings 

      Badawi, Ayman; Anderson, David F. (University of Houston, 2005)
      The purpose of this paper is to introduce two new classes of rings that are closely related to the classes of Dedekind domains and Krull domains. Let H = {R | R is a commutative ring with 1 and Nil(R) is a divided prime ...
    • On phi-Mori rings 

      Badawi, Ayman; Lucas, Thomas G. (University of Houston, 2006)
      A commutative ring R is said to be a phi-ring if its nilradical Nil(R) is both prime and comparable with each principal ideal. The name is derived from the natural map phi from the total quotient ring T(R) to R localized ...
    • On the dot product graph of a commutative ring II 

      Abdulla, Mohammad Ahmad; Badawi, Ayman (International Electronic Journal of Algebra, 2020)
      In 2015, the second-named author introduced the dot product graph associated to a commutative ring A. Let A be a commutative ring with nonzero identity, 1 ≤ n < ∞ be an integer, and R = A × A × · · · × A (n times). We ...
    • On the periodic logistic equation 

      Al-Sharawi, Ziyad; Angelos, James (Elsevier, 2006)
      We show that the 𝒑-periodic logistic equation 𝒳ₙ₊₁ = μₙ mod 𝒑𝒳ₙ(1 - 𝒳ₙ) has cycles (periodic solutions) of minimal periods 1; 𝒑; 2𝒑; 3𝒑; …. Then we extend Singer’s theorem to periodic difference equations, and use ...
    • On weakly 2-absorbing ideals of commutative rings 

      Badawi, Ayman; Darani, Ahmad Yousefian (University of Houston, 2013)
      Let R be a commutative ring with identity 1 not equal to 0. In this paper, we introduce the concept of a weakly 2-absorbing ideal. A proper ideal I of R is called a weakly 2-absorbing ideal of R if whenever abc is not equal ...
    • Option convergence rate with geometric random walks approximations 

      Leduc, Guillaume (Taylor & Frances Online, 2016)
      We describe a broad setting under which, for European options, if the underlying asset form a geometric random walk then, the error with respect to the Black–Scholes model converges to zero at a speed of 1/𝑛 for continuous ...
    • Path Independence of Exotic Options and Convergence of Binomial Approximations 

      Leduc, Guillaume; Palmer, Kenneth J. (Infopro Digital Risk (IP), 2019)
      The analysis of the convergence of tree methods for pricing barrier and lookback options has been the subject of numerous publications aiming at describing, quantifying, and improving the slow and oscillatory convergence ...
    • Periodic Orbits in Periodic Discrete Dynamics 

      Al-Sharawi, Ziyad (Elsevier, 2008)
      We study the combinatorial structure of periodic orbits of nonautonomous difference equations 𝒳ₙ₊₁ = 𝒇ₙ(𝒳ₙ) in a periodically fluctuating environment. We define the Ӷ-set to be the set of minimal periods that are not ...
    • Ramsey numbers of partial order graphs (comparability graphs) and implications in ring theory 

      Badawi, Ayman; Rissner, Roswitha (De Gruyter, 2020)
      For a partially ordered set(A, ≤), letGA be the simple, undirected graph with vertex set A such that two vertices a ≠ ∈ b A are adjacent if either a ≤ b or b a ≤ . We call GA the partial order graph or comparability graph ...
    • A robust method to retrieve option implied risk neutral densities for defaultable assets 

      Leduc, Guillaume; Orosi, Gergely (Inderscience Publishers, 2016)
      Risk neutral densities recovered from option prices can be used to infer market participants' expectations of future stock returns and are a vital tool for pricing illiquid exotic options. Although there is a broad literature ...
    • The solution of a recursive sequence arising from a combinatorial problem in botanical epidemiology 

      Al-Sharawi, Ziyad; Burstein, Alexander; Deadman, Michael; Umar, Abdullahi (Taylor & Francis, 2013)
      One of the central problems in botanical epidemiology is whether disease spreads within crops in a regular pattern or follows a random process. In this paper, we consider a row of n plants in which m are infected. We then ...
    • Some finiteness conditions on the set of overrings of a phi-ring 

      Badawi, Ayman; Jaballah, Ali (University of Houston, 2008)
      Let H = {R | R is a commutative ring and Nil(R) is a divided prime ideal of R}. For a ring R in H with total quotient ring T(R), Let phi be the natural ring homomorphism from T(R) into R_Nil(R). An integral domain R is ...
    • Stability and bifurcation analysis of a discrete-time predator-prey model with strong Allee effect 

      Al-Sharawi, Ziyad; Pal, Saheb; Rana, Sourav; Pal, Nikhil; Chattopadhyay, Joydev (Taylor & Francis, 2020-03-16)
      In this paper, we investigate the impact of Allee effect on the stability of a discrete-time predator-prey model with a non-monotonic functional response. The proposed model supports the coexistence of two steady states, ...
    • Strong ring extensions andphi-pseudo-valuation rings 

      Badawi, Ayman; Dobbs, David E. (University of Houston, 2006)
      In this paper, we extend the concept of strong extensions of domains to the context of (commutative) rings with zero-divisors. We show that the theory of strong extensions of rings resembles that of strong extensions of domains.
    • Weighted multimodal family of distributions with sine and cosine weight functions 

      Alzaatreh, Ayman; Kazempoor, Jaber; Nadi, Adel Ahmadi (Cell Press, 2020)
      In this paper, the moment of various types of sine and cosine functions are derived for any random variable. For an arbitrary even probability density function, the sine and cosine moments are used to define new families ...