There are proved the necessary and sufficient conditions on absolute convergence of Fourier series with respect to generalized Haar systems; sufficient conditions of the absolute summability of multiple trigonometric Fourier series function in Lebesque spaces in terms of modules of smoothness and the best approximation.
Main publications:
Akishev G. O nekotorykh teoremakh dlya sistemy Praisa // Izv. vuzov, seriya matem., 2002 g., # 1, s. 3–8.
Akishev G., Makhashev S. T. Ob absolyutnoi skhodimosti ryadov Fure po obobschennoi sisteme Khaara // Izv. vuzov, 2000 g., # 3, s. 3–11.
Akishev G., Askarova A. Zh. Ob usloviyakh skhodimosti ryadov iz koeffitsientov Fure funktsii mnogikh peremennykh // Izv. Tulskogo gosuniversiteta, 1998, t. 4, # 3, s. 5–11.
Akishev G. O vlozhenii nekotorykh klassov funktsii mnogikh peremennykh v prostranstvo Lorentsa // Izv. AN KazSSR, ser. fiz.-matem., 1982, # 3.
