{"paper":{"title":"Expansions of the ordered additive group of real numbers by two discrete subgroups","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"math.LO","authors_text":"Philipp Hieronymi","submitted_at":"2014-07-25T18:41:22Z","abstract_excerpt":"The theory of $(\\mathbb{R},<,+,\\mathbb{Z},\\mathbb{Z} a)$ is decidable if $a$ is quadratic. If $a$ is the golden ratio, $(\\mathbb{R},<,+,\\mathbb{Z},\\mathbb{Z} a)$ defines multiplication by $a$. The results are established by using the Ostrowski numeration system based on the continued fraction expansion of $a$ to define the above structures in monadic second order logic of one successor. The converse that $(\\mathbb{R},<,+,\\mathbb{Z},\\mathbb{Z} a)$ defines monadic second order logic of one successor, will also be established."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1407.7002","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}