PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY, cilt.146, sa.2, ss.723-731, 2018 (SCI-Expanded)
For Volterra operator V : L-1(0, 1) -> C[0, 1] and summation operators : sigma l(1) -> c, we obtain exact values of Approximation, Gelfand, Kolmogorov and Isomorphism numbers.