A new Ap-A∞ estimate for Calderón-Zygmund operators in spaces of homogeneous type

In this note, we study the Ap-A∞ estimate for Calderón-Zygmund operators in terms of the weak A∞ characteristics in spaces of homogeneous type. The weak A∞ class was introduced recently by Anderson, Hytönen and Tapiola. Our estimate is new even in Euclidean space.