On a characterization of the Shannon entropy
This is a part of a recent program by a number of authors to study information measures on open domain. In this series, this paper is devoted to the study of the functional equation (2) on an open domain. This functional equation is connected to the weighted entropy and weighted entropy of degree a.
The Shannon entropy has the sum form ∑f(pi) with f(x) = -x logx (x belonging to [0,1]). This together with the property of additivity leads to the 'sum' functional equation...