Let {Si}i=1n be generators
of the Cuntz algebra 𝒪n and let Φ be the *-endomorphism of 𝒪n defined by
Φ(x) =∑i=1nSixSi∗. Then both of Connes–Narnhofer–Thirring’s entropy hϕ(Φ)
and Voiculescu’s topological entropy ht(Φ) are logn, where ϕ is the unique
logn-KMS state of 𝒪n. Also Longo’s canonical endomorphism for N ⊂ M
have the same entropy logn, where the inclusion N ⊂ M comes from 𝒪n
.