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arXiv · 2311.15861

Multi-representation associated to the numbering of a subbasis and formal inclusion relations

Emmanuel Rauzy
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Abstract

We revisit Dieter Spreen's notion of a representation associated to a numbered basis equipped with a strong inclusion relation. We show that by relaxing his requirements, we obtain different classically considered representations as subcases, including representations considered by Grubba, Weihrauch and Schröder. We show that the use of an appropriate strong inclusion relation guarantees that the representation associated to a computable metric space seen as a topological space always coincides with the Cauchy representation. We also show how the use of a formal inclusion relation guarantees that when defining multi-representations on a set and on one of its subsets, the obtained multi-representations will be compatible, i.e. inclusion will be a computable map. The proposed definitions are also more robust under change of equivalent bases.

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Emmanuel Rauzy. 2025-09-23. Multi-representation associated to the numbering of a subbasis and formal inclusion relations. https://doi.org/10.46298/lmcs-21(3%3A29)2025

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