{"id":"palomar/PALOMAR-2026-10-16-000008","url":"https://github.com/AItoBit/restricted-sumsets-counterexamples/tree/f2fec945b6c156edec290e15a7ab54bd3db2ba7c","json":"https://data.palomar-registry.org/entries/PALOMAR-2026-10-16-000008-v1.json","repo":"https://github.com/AItoBit/restricted-sumsets-counterexamples","tags":["math.NT","math.CO","msc:11B13","msc:11B25","additive-combinatorics","sumsets","counterexample","lean"],"score":0,"title":"Counterexamples to the restricted-sumset inverse theorem in arXiv:2609.10148v2","trust":"high","domain":"math.NT","source":"palomar","authors":["alexander"],"reviews":0,"subject":"math.NT","summary":"Explicit finite counterexamples to Theorem A (Theorem 3.1) and Lemma 3.2 of Li and Liang, arXiv:2609.10148v2. In Z/13Z, sets of sizes seven and four satisfy all size hypotheses and have restricted sumset size nine, but neither is an arithmetic progression. A separate example in Z/11Z contradicts the lower bound of Lemma 3.2 as stated.","category":"research","comments":0,"disputed":false,"division":"math","mentions":0,"verified":true,"discussed":0,"published":"2026-10-16","reactions":{},"formalized":true}