| 41A10 | [ Approximation by polynomials ] | ||
| 15A18 | [ Eigenvalues, singular values, and eigenvectors ] | ||
| 26D10 | [ Inequalities involving derivatives and differential and integral operators ] | ||
| 35P15 | [ Estimation of eigenvalues, upper and lower bounds ] | ||
| 41A63 | [ Multidimensional problems ] | ||
| 45D05 | [ Volterra integral equations ] |