Stability analysis of a general difference equation under allee effect

Recently, mathematical models and methods have played an important role in interdisciplinary studies. Although we couldn?t solve the problem or phenomena quantatively, we can estimate the solutions by using numerical methods. Solving problems qualitatively in this way has lead to improve different kinds of science, such as biology, ecology and engineering. Also stability analysis could reveal whether the estimated solution is true or not and could give a chance for making sense of behaviour in advance. In this thesis, stability analysis of a general nonlinear delay difference equation X_(t+1)=?X_t f(X_(t-T)) is studied for T=3. Later, the Allee effect function, known as a negative population density function, has been added to the equation. The Allee effect refers to a population that has a maximal per capita growth rate at low density. This effect can be caused by difficulties in, for example, mate finding, social dysfunction at small population sizes, inbreeding depression, food exploitation, and predator avoidance of defence. In conclusion, this model has been compared the situations T=1 and T=2 which had been studied before. It has been shown that the longer the delay be, the greater the destabilizing effect be. In some cases the Allee effect can even annihilate the stability structure. And eventually, the results found have been supported numerically with an example, called `Logistic Difference Equation? by using Matlab.