Andre modeller (SOK-2037 Ressursøkonomi)

Andre modeller

Surplus production

Yield per recruit modelling

The three links above present webMathematica pages where it is possible to calculate (Evaluate) graphs and equations (including analytical equations) of different inputs.

Dynamic systems

Different dynamic systems are presented, all expressed by two differential equations. Equilibriums are shown in phase plots as the intersections between the two isoclines of the system (blue lines). The phase plots also display vector fields representing the dynamics of each system.

Open access

Open access dynamics are well known and could be expressed by the two differential equations below:

A stable solution is found.

Predator - Prey

Lotka - Volterra

A famous predator-prey relationship was expressed by Lotka and Volterra in 1925/1926. The system results in stable cycles (limited cycle), which orbit depends on the intial conditions.

Normal Predator - Prey

A more general expression, opening for stable equilibrium solutions.

Competition

One dominant

The competitive exclusion principle proposed by Gause. The equilibrium defined by the intersection of the two isoclines is not stable, while the two equilibriums where each isocline intersect its own axis are stable.