$BKW$-Operators for Chebyshev Systems
$BKW$-Operators for Chebyshev Systems
This paper is concerned with Korovkin type approximation theorems. We characterize $BKW$-operators on the Banach space of real valued continuous functions on the unit interval for the test functions $\{1,t,t^2,t^3\}$. It is also investigated when subtraction of composition operators are $BKW$-operators for $\{1,t,t^2,t^3,t^4\}$.