{ "id": "2101.11849", "version": "v1", "published": "2021-01-28T07:39:59.000Z", "updated": "2021-01-28T07:39:59.000Z", "title": "On computable aspects of algebraic and definable closure", "authors": [ "Nathanael Ackerman", "Cameron Freer", "Rehana Patel" ], "comment": "20 pages", "doi": "10.1093/logcom/exaa070", "categories": [ "math.LO", "cs.LO" ], "abstract": "We investigate the computability of algebraic closure and definable closure with respect to a collection of formulas. We show that for a computable collection of formulas of quantifier rank at most $n$, in any given computable structure, both algebraic and definable closure with respect to that collection are $\\Sigma^0_{n+2}$ sets. We further show that these bounds are tight.", "revisions": [ { "version": "v1", "updated": "2021-01-28T07:39:59.000Z" } ], "analyses": { "keywords": [ "definable closure", "computable aspects", "quantifier rank", "algebraic closure", "computable collection" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 20, "language": "en", "license": "arXiv", "status": "editable" } } }