Sets of Uniqueness on the 2-Torus

Victor L. Shapiro
1972 Transactions of the American Mathematical Society  
sets are defined on the 2-torus and the following results are established: (1) //"'-sets are sets of uniqueness both for Abel summability and circular convergence of double trigonometric series; (2) a countable union of closed sets of uniqueness of type (A) (i.e., Abel summability) is also a set of uniqueness of type (A).
doi:10.2307/1995878 fatcat:4p7iftale5awzi6kggkwww54ha