Uniform convergence of double trigonometric series
It is shown that under certain conditions on , the rectangular partial sums converge uniformly on . These conditions include conditions of bounded variation of order (1,0), (0,1), and (1,1) with the weights |j|, |k|, |jk|, respectively. The convergence rate is also established. Corresponding to the mentioned conditions, an analogous condition for single trigonometric series is (as n → ∞). For O-regularly varying quasimonotone sequences, we prove that it is equivalent to the condition: as...