@Article{Alpay2024, author = "Alpay, Daniel and Jorgensen, Palle", title = "Finitely additive functions in measure theory and applications", journal = "Opuscula Math.", year = "2024", volume = "44", number = "3", pages = "323--339", doi = "https://doi.org/10.7494/OpMath.2024.44.3.323", url = "https://doi.org/10.7494/OpMath.2024.44.3.323", abstract = "In this paper, we consider, and make precise, a certain extension of the Radon-Nikodym derivative operator, to functions which are additive, but not necessarily sigma-additive, on a subset of a given sigma-algebra. We give applications to probability theory; in particular, to the study of \(\mu\)-Brownian motion, to stochastic calculus via generalized Itô-integrals, and their adjoints (in the form of generalized stochastic derivatives), to systems of transition probability operators indexed by families of measures \(\mu\), and to adjoints of composition operators.", keywords = "Hilbert space, reproducing kernels, probability space, Gaussian fields, transforms, covariance, Itô integration, Itô calculus, generalized Brownian motion", issn = "1232-9274" }