{"paper":{"title":"Improving the trivial bound for $\\ell$-torsion in class groups","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"math.NT","authors_text":"Asif Zaman, Robert J. Lemke Oliver","submitted_at":"2025-02-05T18:59:09Z","abstract_excerpt":"For any number field $K$ with $D_K=|\\mathrm{Disc}(K)|$ and any integer $\\ell \\geq 2$, we improve over the commonly cited trivial bound $|\\mathrm{Cl}_K[\\ell]| \\leq |\\mathrm{Cl}_K| \\ll_{[K:\\mathbb{Q}],\\varepsilon} D_K^{1/2+\\varepsilon}$ on the $\\ell$-torsion subgroup of the class group of $K$ by showing that $|\\mathrm{Cl}_K[\\ell]| = o_{[K:\\mathbb{Q}],\\ell}(D_K^{1/2})$. In fact, we obtain an explicit log-power saving. This is the first general unconditional saving over the trivial bound that holds for all $K$ and all $\\ell$."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2502.03464","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2502.03464/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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"}