# conditional entropy

## English

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### Noun

conditional entropy ‎(plural conditional entropies)

1. (information theory) The portion of a random variable's own Shannon entropy which is independent from another, given, random variable.
The conditional entropy of random variable ${\displaystyle Y}$ given ${\displaystyle X}$ (i.e., conditioned by ${\displaystyle X}$), denoted as ${\displaystyle H(Y|X)}$, is equal to ${\displaystyle H(Y)-I(Y;X)}$ where ${\displaystyle I(Y;X)}$ is the mutual information between ${\displaystyle Y}$ and ${\displaystyle X}$.