{"title":"迭代阴影的交点","authors":"Hou Tin Chau, David Ellis, Marius Tiba","doi":"arxiv-2409.05487","DOIUrl":null,"url":null,"abstract":"We show that if $\\mathcal{A} \\subset {[n] \\choose n/2}$ with measure bounded\naway from zero and from one, then the $\\Omega(\\sqrt{n})$-iterated upper shadows\nof $\\mathcal{A}$ and $\\mathcal{A}^c$ intersect in a set of positive measure.\nThis confirms (in a strong form) a conjecture of Friedgut. It can be seen as a\nstability result for the Kruskal--Katona theorem.","PeriodicalId":501407,"journal":{"name":"arXiv - MATH - Combinatorics","volume":"178 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Intersections of iterated shadows\",\"authors\":\"Hou Tin Chau, David Ellis, Marius Tiba\",\"doi\":\"arxiv-2409.05487\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We show that if $\\\\mathcal{A} \\\\subset {[n] \\\\choose n/2}$ with measure bounded\\naway from zero and from one, then the $\\\\Omega(\\\\sqrt{n})$-iterated upper shadows\\nof $\\\\mathcal{A}$ and $\\\\mathcal{A}^c$ intersect in a set of positive measure.\\nThis confirms (in a strong form) a conjecture of Friedgut. It can be seen as a\\nstability result for the Kruskal--Katona theorem.\",\"PeriodicalId\":501407,\"journal\":{\"name\":\"arXiv - MATH - Combinatorics\",\"volume\":\"178 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-09-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"arXiv - MATH - Combinatorics\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/arxiv-2409.05487\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - MATH - Combinatorics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2409.05487","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
We show that if $\mathcal{A} \subset {[n] \choose n/2}$ with measure bounded
away from zero and from one, then the $\Omega(\sqrt{n})$-iterated upper shadows
of $\mathcal{A}$ and $\mathcal{A}^c$ intersect in a set of positive measure.
This confirms (in a strong form) a conjecture of Friedgut. It can be seen as a
stability result for the Kruskal--Katona theorem.