Stable, semi-stable populations and growth potential.

Area of Science:

• Demography
• Mathematical Biology
• Population Dynamics

Background:

• Recalls Lotka's Malthusian population definition.
• Introduces the concept of a stable population in demography.
• Defines stable population as a limit of demographic processes with constant rates.

Purpose of the Study:

• Define a new concept: the semi-stable population.
• Show that a semi-stable population equals the stable population at any given time.
• Introduce a coefficient of inertia to measure population resistance to demographic changes.

Main Methods:

• Defines semi-stable population based on constant age distribution.
• Establishes formulae for calculating the coefficient of inertia.
• Derives a simplified formula for semi-stable populations.

Main Results:

• A semi-stable population aligns with the stable population of its current fertility and mortality rates.
• The coefficient of inertia formula is simplified for semi-stable populations.
• The simplified formula involves life expectancy, birth rate, and growth rate.

Conclusions:

• The semi-stable population concept provides a new perspective on population dynamics.
• The coefficient of inertia offers a quantifiable measure of population stability.
• The derived formulae facilitate the analysis of population inertia.