Rate of approximation of piecewise-analytic functions by rational fractions in the $L_p$-metrics, $0<p\leqslant\infty$

In this paper estimates are found for $L_pR_n(f)$ – the least deviation in the $L_p$-metric, $0<p\leqslant\infty$, of a piecewise analytic function $f$ from the rational functions of degree at most $n$. It is shown that these estimates are sharp in a well-defined sense.
Bibliography: 13 titles.