For a summary S represented by P S : is maximized for a uniform probability distribution when every semantic unit is present only once in S: ∀(i, j), P S (ω i ) = P S (ω j ).
we define Redundancy, our first quantity relevant to summarization, via entropy: Since H max = log |Ω| is a constant indepedent of S, we can simply write: Redundancy in Previous Works: By definition, entropy encompasses the notion of maximum coverage.