A Univalent Formalization of Constructive Affine Schemes

Autor: Zeuner, Max, Mörtberg, Anders
Rok vydání: 2022
Předmět:
Zdroj: 28th International Conference on Types for Proofs and Programs (TYPES 2022), LIPIcs, volume 269
Druh dokumentu: Working Paper
DOI: 10.4230/LIPIcs.TYPES.2022.14
Popis: We present a formalization of constructive affine schemes in the Cubical Agda proof assistant. This development is not only fully constructive and predicative, it also makes crucial use of univalence. By now schemes have been formalized in various proof assistants. However, most existing formalizations follow the inherently non-constructive approach of Hartshorne's classic "Algebraic Geometry" textbook, for which the construction of the so-called structure sheaf is rather straightforwardly formalizable and works the same with or without univalence. We follow an alternative approach that uses a point-free description of the constructive counterpart of the Zariski spectrum called the Zariski lattice and proceeds by defining the structure sheaf on formal basic opens and then lift it to the whole lattice. This general strategy is used in a plethora of textbooks, but formalizing it has proved tricky. The main result of this paper is that with the help of the univalence principle we can make this "lift from basis" strategy formal and obtain a fully formalized account of constructive affine schemes.
Comment: 22 pages; title changed, introduction and conclusion restructured, typos corrected, references added
Databáze: arXiv