{"title":"极端断开空间的两个选择定理","authors":"Valentin Gutev","doi":"arxiv-2409.09490","DOIUrl":null,"url":null,"abstract":"The paper contains a very simple proof of the classical Hasumi's theorem that\neach usco mapping defined on an extremally disconnected space has a continuous\nselection. The paper also contains a very simple proof of a recent result about\nextension of densely defined continuous selections for compact-valued\ncontinuous mappings, in fact a generalisation of this result to all usco\nmappings with a regular range.","PeriodicalId":501314,"journal":{"name":"arXiv - MATH - General Topology","volume":"15 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Two Selection Theorems for Extremally Disconnected Spaces\",\"authors\":\"Valentin Gutev\",\"doi\":\"arxiv-2409.09490\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The paper contains a very simple proof of the classical Hasumi's theorem that\\neach usco mapping defined on an extremally disconnected space has a continuous\\nselection. The paper also contains a very simple proof of a recent result about\\nextension of densely defined continuous selections for compact-valued\\ncontinuous mappings, in fact a generalisation of this result to all usco\\nmappings with a regular range.\",\"PeriodicalId\":501314,\"journal\":{\"name\":\"arXiv - MATH - General Topology\",\"volume\":\"15 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-09-14\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"arXiv - MATH - General Topology\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/arxiv-2409.09490\",\"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 - General Topology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2409.09490","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Two Selection Theorems for Extremally Disconnected Spaces
The paper contains a very simple proof of the classical Hasumi's theorem that
each usco mapping defined on an extremally disconnected space has a continuous
selection. The paper also contains a very simple proof of a recent result about
extension of densely defined continuous selections for compact-valued
continuous mappings, in fact a generalisation of this result to all usco
mappings with a regular range.