Title THE CONCEPT OF RELATIVE ENTROPY FOR COMPACT SYSTEMS Type Presentation Keywords Entropy, relative dynamical system, invariant, relative measure, relative weighted entropy . Abstract In this paper by use of mathematical modeling of an observer the notion of relative weighted entropy for continuous systems on compact metric spaces is presented. We also extract the Kolmogorov entropy from the relative weighted entropy for ergodic systems from the view point of observer X, where X denotes the base space of the system. Researchers Mohammad Ebrahimi (First researcher)Uosef mohammadi (Second researcher)