{"title":"The GAGA principle","authors":"","doi":"10.1090/mbk/121/44","DOIUrl":"https://doi.org/10.1090/mbk/121/44","url":null,"abstract":"","PeriodicalId":423691,"journal":{"name":"100 Years of Math Milestones","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116965995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An abelian group is finitely generated if there exist finitely many elements a1, a2, . . . , ak such that any element of G can be expressed as a sum c1a1 + c2a2 + . . .+ ckak, where the ci are integers and multiplication denotes repeated addition. Note that this representation need not be unique, so any finite group is also finitely generated. A subgroup of an abelian group G is a set H ⊆ G which is itself a group under the same operation. For any a ∈ G, a+H = {a+ h : h ∈ H} is a coset of H. a is called a representative of the coset a + H. If b ∈ a + H, then b − a ∈ H. Any two cosets of H are either equal or disjoint. The index of H in G, denoted [G : H], is the number of disjoint cosets of H. For a ∈ G, the order of a is the minimum positive integer k such that ka is the identity, or ∞ if there is no such k.
{"title":"Mordell’s theorem","authors":"Jonah Ostroff","doi":"10.1090/mbk/121/09","DOIUrl":"https://doi.org/10.1090/mbk/121/09","url":null,"abstract":"An abelian group is finitely generated if there exist finitely many elements a1, a2, . . . , ak such that any element of G can be expressed as a sum c1a1 + c2a2 + . . .+ ckak, where the ci are integers and multiplication denotes repeated addition. Note that this representation need not be unique, so any finite group is also finitely generated. A subgroup of an abelian group G is a set H ⊆ G which is itself a group under the same operation. For any a ∈ G, a+H = {a+ h : h ∈ H} is a coset of H. a is called a representative of the coset a + H. If b ∈ a + H, then b − a ∈ H. Any two cosets of H are either equal or disjoint. The index of H in G, denoted [G : H], is the number of disjoint cosets of H. For a ∈ G, the order of a is the minimum positive integer k such that ka is the identity, or ∞ if there is no such k.","PeriodicalId":423691,"journal":{"name":"100 Years of Math Milestones","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127068533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ackermann’s function","authors":"","doi":"10.1090/mbk/121/14","DOIUrl":"https://doi.org/10.1090/mbk/121/14","url":null,"abstract":"","PeriodicalId":423691,"journal":{"name":"100 Years of Math Milestones","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114191598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Gale–Shapely algorithm and the stable\u0000 marriage problem","authors":"","doi":"10.1090/mbk/121/50","DOIUrl":"https://doi.org/10.1090/mbk/121/50","url":null,"abstract":"","PeriodicalId":423691,"journal":{"name":"100 Years of Math Milestones","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116298993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}