Shannon entropy

E1168

Shannon entropy is a fundamental measure in information theory that quantifies the average uncertainty or information content in a random variable or message source.

Aliases (3)
  • Shannon additivity axiom ×1
  • Shannon information ×1
  • Shannon limit ×1

Statements (50)
Predicate Object
instanceOf entropy measure
information theory concept
random variable functional
uncertainty measure
appliesTo discrete probability distributions
discrete random variables
captures expected codeword length lower bound in lossless compression
dependsOn probability distribution of a random variable
field information theory
generalizes Hartley entropy
hasFormula H(X) = -\sum_x p(x) \log p(x)
introducedBy Claude Shannon
introducedInWork A Mathematical Theory of Communication
introducedInYear 1948
invariantUnder relabeling of outcomes
isAdditiveFor independent random variables
isConcaveIn probability distribution
isMaximumWhen distribution is uniform
isMinimumWhen distribution is degenerate
isNonNegative true
isSpecialCaseOf Rényi entropy
Tsallis entropy
logarithmBaseDetermines unit of information
measuredIn bits
hartleys
nats
minimumValue 0
namedAfter Claude Shannon
quantifies average information content of a random variable
average uncertainty of a random variable
relatedConcept Kullback–Leibler divergence
conditional entropy
differential entropy
mutual information
relative entropy
satisfies Shannon–Khinchin axioms
chain rule for entropy
symbol H
usedIn bioinformatics
channel coding theory
cryptography
data compression theory
ecology diversity indices
machine learning
neuroscience
signal processing
statistical mechanics
thermodynamics analogies
usedToDefine Shannon capacity of a channel
entropy rate of a stochastic process


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