更改

:<math>\Eta(X|Y) = \Eta(X,Y) - \Eta(Y)\,</math>,

:<math>H(X|Y) = H(X,Y) - H(Y)\,</math>,

and <math display="block">\Eta(X_1,\dots,X_n) = \sum_{k=1}^n \Eta(X_k|X_{k-1},\dots, X_1)</math>

and <math display="block">H(X_1,\dots,X_n) = \sum_{k=1}^n H(X_k|X_{k-1},\dots, X_1)</math>

It is also used in the definition of [[mutual information]]<ref name=cover1991 />{{rp|21}}

It is also used in the definition of [[mutual information]]<ref name=cover1991 />{{rp|21}}

:<math>\operatorname{I}(X;Y) = \Eta(X) + \Eta(Y) - \Eta(X,Y)\,</math>

:<math>\operatorname{I}(X;Y) = H(X) + H(Y) - H(X,Y)\,</math>