Boundedness and compactness of commutators associated with Lipschitz functions

Let $alphain (0, 1]$, $betain [0, n)$ and $T_{Omega,beta}$ be a singular or fractional integral operator with homogeneous kernel $Omega$. In this article, a CMO type space ${rm CMO}_alpha(mathbb R^n)$ is introduced and studied. In particular, the relationship between ${rm CMO}_alpha(mathbb R^n)$ and the Lipchitz space $Lip_alpha(mathbb R^n)$ is discussed. Moreover, a necessary condition of restricted boundedness of the iterated commutator $(T_{Omega,beta})^m_b$ on weighted Lebesgue spaces via functions in $Lip_alpha(mathbb R^n)$, and an equivalent characterization of the compactness for $(T_{Omega,beta})^m_b$ via functions in ${rm CMO}_alpha(mathbb R^n)$ are obtained. Some results are new even in the unweighted setting for the first order commutators.