New Characterizations and Properties of Matrix A∞ Weights
摘要
We provide several new characterizations of Ap,∞-matrix weights, originally introduced by A. Volberg in [J. Amer. Math. Soc., 10, 445–466 (1997)] as matrix-valued substitutes of the classical Muckenhoupt A∞ weights. In analogy with the concept of Ap-dimensions of matrix weights introduced in our previous work, we introduce the concepts of the lower and the upper dimensions of Ap,∞-matrix weights, which enable us to obtain sharp estimates related to their reducing operators. In a companion article by the same authors, these results play a key role in the study of function spaces with Ap,∞-matrix weights, which extends earlier results in the more restricted class of Ap-matrix weights.