Abstract:
Earlier the second author showed that, in the periodic case, the rate of best uniform rational approximations of a function is well described in terms of the rates of best uniform piecewise polynomial approximations of the function itself and its conjugate. In the present paper, a similar result is obtained for a closed interval.
Keywords:best uniform rational approximation of a function, best uniform piecewise polynomial approximation, $L_p$-modulus of smoothness, Besov space $B_p^\alpha$, Jordan curve, Szegö-type inequality.