e-learning; adaptive; system; learning styles; rules

This article describes rule based system of adaptive e-learning. Elemental part of this system are rules that are thoroughly described together with different types of their categorization. There is also briefly described the engine that uses this rules, how are they applied, how can they interoperate and collaborate and how are avoided all conflicts in rules. This rule based engine was used in adaptive system Barborka 4 that was used in two successful pedagogical experiments in two Ph. D. thesis.