{ "id": "2204.10991", "version": "v1", "published": "2022-04-23T04:58:16.000Z", "updated": "2022-04-23T04:58:16.000Z", "title": "A new perspective on semi-retractions and the Ramsey property", "authors": [ "Dana Bartošová", "Lynn Scow" ], "comment": "27 pages", "categories": [ "math.LO", "math.CO" ], "abstract": "We investigate the notion of a semi-retraction between two first order structures (in typically different languages) that was introduced by the second author as a link between the Ramsey property and generalized indiscernible sequences. We further these connections between combinatorics and model theory, and look at semi-retractions through a new lens establishing transfers of the Ramsey property and finite Ramsey degrees under quite general conditions that are optimal as demonstrated by counterexamples. Finally, we compare semi-retractions to the category theoretic notion of a pre-adjunction.", "revisions": [ { "version": "v1", "updated": "2022-04-23T04:58:16.000Z" } ], "analyses": { "keywords": [ "ramsey property", "semi-retraction", "first order structures", "category theoretic notion", "finite ramsey degrees" ], "note": { "typesetting": "TeX", "pages": 27, "language": "en", "license": "arXiv", "status": "editable" } } }