{"title":"精确的子类别、子函子和一些应用程序","authors":"HAILONG DAO, SOUVIK DEY, MONALISA DUTTA","doi":"10.1017/nmj.2023.29","DOIUrl":null,"url":null,"abstract":"Abstract Let $({\\cal{A}},{\\cal{E}})$ be an exact category. We establish basic results that allow one to identify sub(bi)functors of ${\\operatorname{Ext}}_{\\cal{E}}(-,-)$ using additivity of numerical functions and restriction to subcategories. We also study a small number of these new functors over commutative local rings in detail and find a range of applications from detecting regularity to understanding Ulrich modules.","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":"{\"title\":\"EXACT SUBCATEGORIES, SUBFUNCTORS OF , AND SOME APPLICATIONS\",\"authors\":\"HAILONG DAO, SOUVIK DEY, MONALISA DUTTA\",\"doi\":\"10.1017/nmj.2023.29\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Abstract Let $({\\\\cal{A}},{\\\\cal{E}})$ be an exact category. We establish basic results that allow one to identify sub(bi)functors of ${\\\\operatorname{Ext}}_{\\\\cal{E}}(-,-)$ using additivity of numerical functions and restriction to subcategories. We also study a small number of these new functors over commutative local rings in detail and find a range of applications from detecting regularity to understanding Ulrich modules.\",\"PeriodicalId\":0,\"journal\":{\"name\":\"\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0,\"publicationDate\":\"2023-09-27\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"2\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1017/nmj.2023.29\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1017/nmj.2023.29","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
EXACT SUBCATEGORIES, SUBFUNCTORS OF , AND SOME APPLICATIONS
Abstract Let $({\cal{A}},{\cal{E}})$ be an exact category. We establish basic results that allow one to identify sub(bi)functors of ${\operatorname{Ext}}_{\cal{E}}(-,-)$ using additivity of numerical functions and restriction to subcategories. We also study a small number of these new functors over commutative local rings in detail and find a range of applications from detecting regularity to understanding Ulrich modules.