Asymptotic dynamics of generalized Kantorovich operators
Krzysztof Bartoszek, Wojciech Bartoszek
TL;DR
This work characterizes exactly which continuous functions $f$ on a compact space admit uniform convergence of the iterates of a generalized Kantorovich Markov operator $\widehat{T}_i$. By proving a general convergence theorem (Theorem 2.1) for Markov operators with an open dense invariant domain $X_{\lambda}$ and a strongly ergodic complement, it provides necessary and sufficient conditions tied to invariant measures $\lambda$ and Cesàro means. As an application, it resolves Acu and Rasa's conjecture: for $X=[0,1]$ the iterates of $\widehat{T}_i$ converge uniformly on $[0,1]$ exactly when $\int_0^1 f(u)\,du = f(1)$, with the limit being $\big(\int_0^1 f\,d\lambda\big)\mathbf{1}$. This advances understanding of diffusion-type Markov operators and provides a precise criterion linking boundary values to long-term averaging behavior.
Abstract
We characterize the family of continuous functions $f\in C([0,1])$ such that the iterates $\widehat{T}^{k}_{i} f$ converge uniformly on $[0,1]$, where $\widehat{T}_i$ is a generalized Kantorovich operator. This gives an affirmative answer to the problem raised in 2021 by Acu and Rasa.
