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We study weak amenability of certain classes of commutative semigroup algebras. First, we present a class of commutative semigroups which their semigroup algebras (like arbitrary group algebras) are always $2n$-weakly amenable. Weak amenability of $\ell^1(S)$ in terms of regular and irregular subsets of a commutative semigroup $S$ is also studied.
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