Year: 2026
Type: preprint
Abstract: For every right-c.e.\ real $p\in(1,2)$, $L^p[0,1]$ has a computable presentation. The proof combines an effective stability modulus for almost isometric embeddings with a Fra\"ıssé-style construction in which the exponent varies. In the same range, if $\ell^p$ has a computable presentation, then $p$ is computable. Combining these with the known results gives the computable presentability classification for all separable Lebesgue spaces. We also formulate an effective Fra\"ıssé theorem for Banach spaces and apply it to obtain a computable presentation of the Gurarij Banach space.
Source: arXiv (Cornell University)
Authors: Xie, Ruofei, Zhao, Xuanheng
Institution: Nanjing University
Language: English
Topic: Advanced Banach Space Theory
Subfield: Mathematical Physics
Field: Mathematics
Domain: Physical Sciences
Open Access status: green
Award: G5414997189
OpenAlex ID: W7223387229