Question: Lotka-Volterra system

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SUMMARY

The discussion focuses on the Lotka-Volterra system represented by the equations x'_1 = (a-bx_2)x_1 and x'_2 = (cx_1 -d)x_2, where a, b, c, and d are positive constants. The objective is to demonstrate that this system is integrable, indicating the existence of a C^1-function F: U → ℝ, defined on an open subset U of the first quadrant K. Key insights include the necessity of finding a constant of motion, which has a time derivative of zero, and understanding the definition of "integrable" to proceed with the proof.

PREREQUISITES
  • Understanding of the Lotka-Volterra model and its equations.
  • Knowledge of C^1-functions and their properties.
  • Familiarity with the concept of integrability in dynamical systems.
  • Basic calculus, particularly in relation to derivatives and motion constants.
NEXT STEPS
  • Research the definition and properties of integrable systems in dynamical systems theory.
  • Learn how to find constants of motion for differential equations.
  • Study the implications of C^1-functions in the context of dynamical systems.
  • Explore the geometric interpretation of trajectories in the Lotka-Volterra model.
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Mathematicians, students studying dynamical systems, and researchers interested in ecological modeling or systems biology will benefit from this discussion.

mathboy20
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Hi

I need help intepreting the following.

Given Lotka-Volterra model system

\begin{array}{cc} x'_1 = (a-bx_2)x_1 \\ x'_2 = (cx_1 -d) x_2\end{array}

Look at the system on the open 1.Quadrant K; where a,b,c,d are all positive constants.

Show that the system is integratable, which supposedly implies that there exist a C^1-function F:U \rightarrow \mathbb{R} where U \subseteq K is open, and close in K.

According to my professor "close" implies that for every point in K, there exist a sequence of socalled "limitpoints", who's elements belongs to K. Also as a consequence of "close" \nabla F \neq 0 for all x \in U, and F is constant on all trajectories of the system.

What is my first step here? Do I prove that there exist a solution for the system only in K?

Sincerley Yours
Mathboy20
 
Last edited:
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Volterra

To begin with you need to find a function of two variables (x_1, x_2) which is a constant of motion. i.e. its time derivative is zero. Then you worry where it is defined.
 
You might also want to look up the definition of "integrable" since that is what you are asked to show!
 

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