Demirci, KamilDirik, FadimeYildiz, Sevda2025-03-232025-03-2320251422-63831420-9012https://doi.org/10.1007/s00025-025-02366-whttps://hdl.handle.net/11486/7010In this paper, we use the power series methods to study Korovkin-type approximation theorems for sequences of operators that are monotone and sublinear. It is important to point out that any positive linear operator is monotone sublinear but the converse is not true. We also calculate the rate of convergence in terms of modulus of continuity. Finally, we provide some examples that satisfy our theorems and give quantitative estimates. We also define Bernstein-Chlodovsky-Kantorovich-Choquet (BCKC) polynomial operators similar to those given before and obtain approximation estimate.eninfo:eu-repo/semantics/closedAccessPower series methodmonotone and sublinear operatorsnonlinear Choquet integralArticle80210.1007/s00025-025-02366-w2-s2.0-85218841163Q2WOS:001423555600002Q1