A general theorem on the existance of lipshitz retractions on certain surfaces was proved.<br> As a corollary, a lipshitz $\varepsilon$-selection on the set of generalised rational functions was constructed. Several results, concerning the problem of existance of continuous selections from the operator of generalised rational approximation in $L_p$, $0<p\le\infty$ spaces were obtained. It was proved that pseudodimension of any set is greater or equal than its topological dimension.
Main publications:
Lipshitsevost retraktsii i operator obobschennogo ratsionalnogo priblizheniya // Fundament. i prikl. matem., 2000, # 4, s. 1205–1220.
Ravnomernaya nepreryvnost obobschennykh ratsionalnykh priblizhenii // Matematicheskie zametki, 2002, t. 71, # 2, s. 261–270.
Otsenka snizu psevdorazmernosti cherez topologicheskuyu // Matematicheskie zametki, 2001, t. 70, # 1, s. 155–156.
