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Now showing items 1-10 of 12

#### On phi-Mori rings

(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 ...

#### Existence and stability of periodic orbits of periodic difference equations with delays

(World Scientific Publishing, 2008)

In this paper, we investigate the existence and stability of periodic orbits of the p-periodic difference equation with delays xₙ = f(n - 1, xₙ₋ₖ). We show that the periodic orbits of this equation depend on the periodic ...

#### On phi-Dedekind rings and phi-Krull rings

(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 the periodic logistic equation

(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 ...

#### Strong ring extensions andphi-pseudo-valuation rings

(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.

#### An Extension of Sharkovsy’s Theorem to Periodic Difference Equations

(Elsevier, 2006)

We present an extension of Sharkovsky’s Theorem and its converse to periodic difference equations. In addition, we provide a simple method for constructing a p-periodic difference equation having an r-periodic geometric ...

#### Exercisability Randomization of the American Option

(Taylor & Frances Online, 2008)

The valuation of American options is an optimal stopping time problem which typically leads to a free boundary problem. We introduce here the randomization of the exercisability of the option. This method considerably ...

#### Coexistence and extinction in a competitive exclusion Leslie/Gower model with harvesting and stocking

(Taylor & Francis Online, 2009)

The principle of competitive exclusion states that when the competition between species is sufficiently strong, only the dominant species survives. In this paper, we examine the strategies of using stocking and harvesting ...

#### The Beverton–Holt model with periodic and conditional harvesting

(Taylor & Francis Online, 2009)

In this theoretical study, we investigate the effect of different harvesting strategies on the discrete Beverton–Holt model in a deterministic environment. In particular, we make a comparison between the constant, periodic ...

#### Martingale problem for superprocesses with non-classical branching functional

(Elsevier, 2006)

The martingale problem for superprocesses with parameters (𝛏, Ф, 𝑘) is studied where 𝑘(𝒹𝑠) may not be absolutely continuous with respect to the Lebesgue measure. This requires a generalization of the concept of ...