Entropy Coherent and Entropy Convex Measures of Risk - Eurandom
Entropy Coherent and Entropy Convex Measures of Risk - Eurandom
Entropy Coherent and Entropy Convex Measures of Risk - Eurandom
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<strong>Entropy</strong> Coherence <strong>and</strong> <strong>Entropy</strong> <strong>Convex</strong>ity<br />
Definition<br />
We call a mapping ρ : L ∞ → R γ-entropy coherent, γ ∈ [0, ∞], if there exists a<br />
set M ⊂ Q such that<br />
ρ(X) = sup eγ,Q(X).<br />
Q∈M<br />
It will be interesting to consider as well a more general class <strong>of</strong> risk measures:<br />
Definition<br />
The mapping ρ : L ∞ → R is γ-entropy convex, γ ∈ [0, ∞], if there exists a<br />
penalty function c : Q → [0, ∞] with infQ∈Q c(Q) = 0, such that<br />
ρ(X) = sup {eγ,Q(X) − c(Q)}.<br />
Q∈Q<br />
<strong>Entropy</strong> <strong>Coherent</strong> <strong>and</strong> <strong>Entropy</strong> <strong>Convex</strong> <strong>Measures</strong> <strong>of</strong> <strong>Risk</strong> Advances in Financial Mathematics, Eur<strong>and</strong>om, Eindhoven 21/40