New results on the constrained mock-Chebyshev least squares operator

In this paper, we extend the constrained mock-Chebyshev least squares operator to quasi-uniform grids, preserving the accuracy and applicability of the original approach while addressing the practical challenge of quasi-equispaced nodes. Additionally, we provide an improved bound for the norm of the operator by using a refined bound for its coefficient vector through the direct elimination method. Numerical experiments confirm the efficiency of the proposed technique.