scholarly journals Exact Reduction of the Generalized Lotka–Volterra Equations via Integral and Algebraic Substitutions

Computation ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 49
Author(s):  
Rebecca E. Morrison

Systems of interacting species, such as biological environments or chemical reactions, are often described mathematically by sets of coupled ordinary differential equations. While a large number β of species may be involved in the coupled dynamics, often only α<β species are of interest or of consequence. In this paper, we explored how to construct models that include only those given α species, but still recreate the dynamics of the original β-species model. Under some conditions detailed here, this reduction can be completed exactly, such that the information in the reduced model is exactly the same as the original one, but over fewer equations. Moreover, this reduction process suggests a promising type of approximate model—no longer exact, but computationally quite simple.

1998 ◽  
Vol 3 (1) ◽  
pp. 25-32
Author(s):  
Jânis Cepîtis ◽  
Harijs Kalis

The mathematical model of a chemical reaction which takes place on the surface of the uniformly moving vertically imbedded glass fibre material is considered. The effect of gravitation is taken into account. Boussinesq's and boundary layer fittings allow to derive boundary value problems for self‐similar systems of ordinary differential equations.


1993 ◽  
Vol 01 (03) ◽  
pp. 275-309 ◽  
Author(s):  
A. PAVÉ

A framework for interpretation of classical populations dynamics models written in terms of ordinary differential equations and related to biological mechanisms is proposed. This approach is based on the construction of functional schemes, similar to those used to symbolize chemical reactions. These schemes can be associated to differential equations which formalize the kinetics of these reactions. So schemes associated to classical one-species models are given (exponential, logistic, Gompertz, and Kostitzin models). Some typical cases of two species models proposed by Lotka and Volterra (predator-prey and competition models) are also explored.


Author(s):  
Nikolay I. Kol'tsov

It is known that chaotic oscillations for chemical reactions can be described by non-stationary kinetic models consisting of three ordinary differential equations.  Rossler established the first examples of chemical reactions, including the two-route five-stage reaction of the Villamovski-Rossler, with three intermediate substances, containing three autocatalytic on intermediates stages, the dynamic model of which describes chaotic oscillations. In given article presents a simple one-route four-stages reaction A+E=D involving two autocatalytic and one linear on intermediate stage, the non-stationary kinetic model of which describes chaotic oscillations. The non-stationary kinetic model under the assumption of quasistationarity with respect to the main substances within the framework of the law of acting masses is a system of three ordinary differential equations. The presence of chaos is confirmed by numerical calculations of the kinetic model and Lyapunov exponentials. The Lyapunov exponents satisfy the condition L1+L2+L3<0, which proves the existence of chaotic oscillations.Forcitation:Kol'tsov N.I. Chaotic oscillations in simplest chemical reaction. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 4-5. P. 133-135


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