{"title":"带有 CH 否定和弱强制公理的 C(X) 上的不连续同构","authors":"Yushiro Aoki","doi":"10.1112/jlms.12956","DOIUrl":null,"url":null,"abstract":"<p>In this paper, I introduce the properties <span></span><math>\n <semantics>\n <msub>\n <mi>EPC</mi>\n <msub>\n <mi>ℵ</mi>\n <mn>1</mn>\n </msub>\n </msub>\n <annotation>$\\mathrm{EPC}_{\\aleph _1}$</annotation>\n </semantics></math> and <span></span><math>\n <semantics>\n <mrow>\n <mi>ProjCes</mi>\n <mo>(</mo>\n <mi>E</mi>\n <mo>)</mo>\n </mrow>\n <annotation>$\\mathrm{ProjCes}(E)$</annotation>\n </semantics></math> for forcing notions and show that it is consistent that the forcing axiom for <span></span><math>\n <semantics>\n <mrow>\n <msub>\n <mi>EPC</mi>\n <msub>\n <mi>ℵ</mi>\n <mn>1</mn>\n </msub>\n </msub>\n <mo>+</mo>\n <mi>ProjCes</mi>\n <mrow>\n <mo>(</mo>\n <mi>E</mi>\n <mo>)</mo>\n </mrow>\n </mrow>\n <annotation>$\\mathrm{EPC}_{\\aleph _1}+ \\mathrm{ProjCes}(E)$</annotation>\n </semantics></math> forcing notions holds, the continuum hypothesis fails, and an ultrapower of the field of reals has the property <span></span><math>\n <semantics>\n <msub>\n <mi>β</mi>\n <mn>1</mn>\n </msub>\n <annotation>$\\beta _1$</annotation>\n </semantics></math>. This provides a partial solution to H. Woodin's question concerning the existence of discontinuous homomorphisms on the Banach algebra of all complex-valued continuous functions on a compact space. Furthermore, we prove that the uniformization of a coloring of a ladder system on a stationary–costationary set <span></span><math>\n <semantics>\n <mi>E</mi>\n <annotation>$E$</annotation>\n </semantics></math> is an example of an <span></span><math>\n <semantics>\n <mrow>\n <msub>\n <mi>EPC</mi>\n <msub>\n <mi>ℵ</mi>\n <mn>1</mn>\n </msub>\n </msub>\n <mo>+</mo>\n <mi>ProjCes</mi>\n <mrow>\n <mo>(</mo>\n <msub>\n <mi>ω</mi>\n <mn>1</mn>\n </msub>\n <mo>∖</mo>\n <mi>E</mi>\n <mo>)</mo>\n </mrow>\n </mrow>\n <annotation>$\\mathrm{EPC}_{\\aleph _1}+ \\mathrm{ProjCes}(\\omega _1 \\setminus E)$</annotation>\n </semantics></math> forcing notion. As a corollary, it is consistent that a nonfree Whitehead group exists, the continuum hypothesis fails, and an ultrapower of the field of reals has the property <span></span><math>\n <semantics>\n <msub>\n <mi>β</mi>\n <mn>1</mn>\n </msub>\n <annotation>$\\beta _1$</annotation>\n </semantics></math>.</p>","PeriodicalId":49989,"journal":{"name":"Journal of the London Mathematical Society-Second Series","volume":"110 1","pages":""},"PeriodicalIF":1.0000,"publicationDate":"2024-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Discontinuous homomorphisms on C(X) with the negation of CH and a weak forcing axiom\",\"authors\":\"Yushiro Aoki\",\"doi\":\"10.1112/jlms.12956\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>In this paper, I introduce the properties <span></span><math>\\n <semantics>\\n <msub>\\n <mi>EPC</mi>\\n <msub>\\n <mi>ℵ</mi>\\n <mn>1</mn>\\n </msub>\\n </msub>\\n <annotation>$\\\\mathrm{EPC}_{\\\\aleph _1}$</annotation>\\n </semantics></math> and <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>ProjCes</mi>\\n <mo>(</mo>\\n <mi>E</mi>\\n <mo>)</mo>\\n </mrow>\\n <annotation>$\\\\mathrm{ProjCes}(E)$</annotation>\\n </semantics></math> for forcing notions and show that it is consistent that the forcing axiom for <span></span><math>\\n <semantics>\\n <mrow>\\n <msub>\\n <mi>EPC</mi>\\n <msub>\\n <mi>ℵ</mi>\\n <mn>1</mn>\\n </msub>\\n </msub>\\n <mo>+</mo>\\n <mi>ProjCes</mi>\\n <mrow>\\n <mo>(</mo>\\n <mi>E</mi>\\n <mo>)</mo>\\n </mrow>\\n </mrow>\\n <annotation>$\\\\mathrm{EPC}_{\\\\aleph _1}+ \\\\mathrm{ProjCes}(E)$</annotation>\\n </semantics></math> forcing notions holds, the continuum hypothesis fails, and an ultrapower of the field of reals has the property <span></span><math>\\n <semantics>\\n <msub>\\n <mi>β</mi>\\n <mn>1</mn>\\n </msub>\\n <annotation>$\\\\beta _1$</annotation>\\n </semantics></math>. This provides a partial solution to H. Woodin's question concerning the existence of discontinuous homomorphisms on the Banach algebra of all complex-valued continuous functions on a compact space. Furthermore, we prove that the uniformization of a coloring of a ladder system on a stationary–costationary set <span></span><math>\\n <semantics>\\n <mi>E</mi>\\n <annotation>$E$</annotation>\\n </semantics></math> is an example of an <span></span><math>\\n <semantics>\\n <mrow>\\n <msub>\\n <mi>EPC</mi>\\n <msub>\\n <mi>ℵ</mi>\\n <mn>1</mn>\\n </msub>\\n </msub>\\n <mo>+</mo>\\n <mi>ProjCes</mi>\\n <mrow>\\n <mo>(</mo>\\n <msub>\\n <mi>ω</mi>\\n <mn>1</mn>\\n </msub>\\n <mo>∖</mo>\\n <mi>E</mi>\\n <mo>)</mo>\\n </mrow>\\n </mrow>\\n <annotation>$\\\\mathrm{EPC}_{\\\\aleph _1}+ \\\\mathrm{ProjCes}(\\\\omega _1 \\\\setminus E)$</annotation>\\n </semantics></math> forcing notion. As a corollary, it is consistent that a nonfree Whitehead group exists, the continuum hypothesis fails, and an ultrapower of the field of reals has the property <span></span><math>\\n <semantics>\\n <msub>\\n <mi>β</mi>\\n <mn>1</mn>\\n </msub>\\n <annotation>$\\\\beta _1$</annotation>\\n </semantics></math>.</p>\",\"PeriodicalId\":49989,\"journal\":{\"name\":\"Journal of the London Mathematical Society-Second Series\",\"volume\":\"110 1\",\"pages\":\"\"},\"PeriodicalIF\":1.0000,\"publicationDate\":\"2024-06-30\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of the London Mathematical Society-Second Series\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1112/jlms.12956\",\"RegionNum\":2,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the London Mathematical Society-Second Series","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1112/jlms.12956","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
Discontinuous homomorphisms on C(X) with the negation of CH and a weak forcing axiom
In this paper, I introduce the properties and for forcing notions and show that it is consistent that the forcing axiom for forcing notions holds, the continuum hypothesis fails, and an ultrapower of the field of reals has the property . This provides a partial solution to H. Woodin's question concerning the existence of discontinuous homomorphisms on the Banach algebra of all complex-valued continuous functions on a compact space. Furthermore, we prove that the uniformization of a coloring of a ladder system on a stationary–costationary set is an example of an forcing notion. As a corollary, it is consistent that a nonfree Whitehead group exists, the continuum hypothesis fails, and an ultrapower of the field of reals has the property .
期刊介绍:
The Journal of the London Mathematical Society has been publishing leading research in a broad range of mathematical subject areas since 1926. The Journal welcomes papers on subjects of general interest that represent a significant advance in mathematical knowledge, as well as submissions that are deemed to stimulate new interest and research activity.