2020/11/01 by Tom Leinster, Leinster, Tom · 2 citations
Mathematics · #Advanced Banach Space Theory #Approximation Theory and Sequence Spaces #Category Theory (math.CT) #FOS: Mathematics #Functional Analysis (math.FA)
paper · pdf · doi:10.48550/arxiv.2011.00412
openalex publication_date 2020/11/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We identify simple universal properties that uniquely characterize the Lebesgue Lp spaces. There are two main theorems. The first states that the Banach space Lp[0, 1], equipped with a small amount of extra structure, is initial as such. The second states that the Lp functor on finite measure spaces, again with some extra structure, is also initial as such. In both cases, the universal characterization of the integrable functions produces a unique characterization of integration. Using the universal properties, we develop some of the basic elements of integration theory. We also state universal properties characterizing the sequence spaces ℓp and c0, as well as the functor L2 taking values in Hilbert spaces.