Korovkin type approximation theorems on the disk algebra
Korovkin type approximation theorems on the disk algebra
We investigate BKW-0perators on the disk algebra for the test functions \{1, z, z^{2}\} having forms as T=(C_{\varphi}+C_{\psi})/2 , |\varphi|=|\psi|=1 on the unit circle.Our studies have some relation to extremal problems on Hardy spaces.