Weak amenability of commutative Beurling algebras

For a locally compact Abelian group $G$ and a continuous weight function $\omega$ on $G$ we show that the Beurling algebra $L^1(G,\omega )$ is weakly amenable if and only if there is no nontrivial continuous group homomorphism $\varphi$: $G\to \mathbb{C}$ such that $\sup_{t\in G}\frac{|\phi(t)|}{\omega(t)\omega(t^{-1})} < \infty$\mathrm{.}Let$\hat\omega(t) = \limsup_{s\to \infty}\omega(ts)/\omega(s)$($t\in G$)\mathrm{.}Then$L^1(G, \omega)$ is 2-weakly amenable if there is a constant $m>0$ such that $\liminf_{n\to \infty}\frac{\omega(t^n)\hat\omega(t^{-n})}{n} \leq m$forall$t\in G$.