ばいちょ(売価調査)、価格比較とネットでのお買い物を楽に

内容説明 This book presents in a coherent way the results obtained in the following aspects of the theory of multiple trigonometric Fourier series: the existence and properties of the conjugates and Hilbert transforms of integrable functions of several variables; convergence of Fourier series and their conjugates， as well as their summability by Ces-ro and Abel-Poisson methods; and approximating properties of Ces-ro means of Fourier series and their conjugates. Special emphasis is put on new effects which arise from dealing with multiple series and which are not inherent in the one-dimensional case. Unsolved problems are formulated separately. Audience: This volume will prove useful to both graduate students and research workers in the field of Fourier analysis， approximations and expansions， integral transforms， and operational calculus.