{"title":"强迫公理和非定常理想的复杂性。","authors":"Sean Cox, Philipp Lücke","doi":"10.1007/s00605-022-01734-w","DOIUrl":null,"url":null,"abstract":"<p><p>We study the influence of strong forcing axioms on the complexity of the non-stationary ideal on <math><msub><mi>ω</mi> <mn>2</mn></msub> </math> and its restrictions to certain cofinalities. Our main result shows that the strengthening <math> <msup><mrow><mi>MM</mi></mrow> <mrow><mo>+</mo> <mo>+</mo></mrow> </msup> </math> of Martin's Maximum does not decide whether the restriction of the non-stationary ideal on <math><msub><mi>ω</mi> <mn>2</mn></msub> </math> to sets of ordinals of countable cofinality is <math><msub><mi>Δ</mi> <mn>1</mn></msub> </math> -definable by formulas with parameters in <math><mrow><mi>H</mi> <mo>(</mo> <msub><mi>ω</mi> <mn>3</mn></msub> <mo>)</mo></mrow> </math> . The techniques developed in the proof of this result also allow us to prove analogous results for the full non-stationary ideal on <math><msub><mi>ω</mi> <mn>2</mn></msub> </math> and strong forcing axioms that are compatible with <math><mi>CH</mi></math> . Finally, we answer a question of S. Friedman, Wu and Zdomskyy by showing that the <math><msub><mi>Δ</mi> <mn>1</mn></msub> </math> -definability of the non-stationary ideal on <math><msub><mi>ω</mi> <mn>2</mn></msub> </math> is compatible with arbitrary large values of the continuum function at <math><msub><mi>ω</mi> <mn>2</mn></msub> </math> .</p>","PeriodicalId":54737,"journal":{"name":"Monatshefte fur Mathematik","volume":"199 1","pages":"45-84"},"PeriodicalIF":0.8000,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9388474/pdf/","citationCount":"0","resultStr":"{\"title\":\"Forcing axioms and the complexity of non-stationary ideals.\",\"authors\":\"Sean Cox, Philipp Lücke\",\"doi\":\"10.1007/s00605-022-01734-w\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>We study the influence of strong forcing axioms on the complexity of the non-stationary ideal on <math><msub><mi>ω</mi> <mn>2</mn></msub> </math> and its restrictions to certain cofinalities. Our main result shows that the strengthening <math> <msup><mrow><mi>MM</mi></mrow> <mrow><mo>+</mo> <mo>+</mo></mrow> </msup> </math> of Martin's Maximum does not decide whether the restriction of the non-stationary ideal on <math><msub><mi>ω</mi> <mn>2</mn></msub> </math> to sets of ordinals of countable cofinality is <math><msub><mi>Δ</mi> <mn>1</mn></msub> </math> -definable by formulas with parameters in <math><mrow><mi>H</mi> <mo>(</mo> <msub><mi>ω</mi> <mn>3</mn></msub> <mo>)</mo></mrow> </math> . The techniques developed in the proof of this result also allow us to prove analogous results for the full non-stationary ideal on <math><msub><mi>ω</mi> <mn>2</mn></msub> </math> and strong forcing axioms that are compatible with <math><mi>CH</mi></math> . Finally, we answer a question of S. Friedman, Wu and Zdomskyy by showing that the <math><msub><mi>Δ</mi> <mn>1</mn></msub> </math> -definability of the non-stationary ideal on <math><msub><mi>ω</mi> <mn>2</mn></msub> </math> is compatible with arbitrary large values of the continuum function at <math><msub><mi>ω</mi> <mn>2</mn></msub> </math> .</p>\",\"PeriodicalId\":54737,\"journal\":{\"name\":\"Monatshefte fur Mathematik\",\"volume\":\"199 1\",\"pages\":\"45-84\"},\"PeriodicalIF\":0.8000,\"publicationDate\":\"2022-01-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9388474/pdf/\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Monatshefte fur Mathematik\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.1007/s00605-022-01734-w\",\"RegionNum\":4,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"2022/6/27 0:00:00\",\"PubModel\":\"Epub\",\"JCR\":\"Q2\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Monatshefte fur Mathematik","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1007/s00605-022-01734-w","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2022/6/27 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
Forcing axioms and the complexity of non-stationary ideals.
We study the influence of strong forcing axioms on the complexity of the non-stationary ideal on and its restrictions to certain cofinalities. Our main result shows that the strengthening of Martin's Maximum does not decide whether the restriction of the non-stationary ideal on to sets of ordinals of countable cofinality is -definable by formulas with parameters in . The techniques developed in the proof of this result also allow us to prove analogous results for the full non-stationary ideal on and strong forcing axioms that are compatible with . Finally, we answer a question of S. Friedman, Wu and Zdomskyy by showing that the -definability of the non-stationary ideal on is compatible with arbitrary large values of the continuum function at .
期刊介绍:
The journal was founded in 1890 by G. v. Escherich and E. Weyr as "Monatshefte für Mathematik und Physik" and appeared with this title until 1944. Continued from 1948 on as "Monatshefte für Mathematik", its managing editors were L. Gegenbauer, F. Mertens, W. Wirtinger, H. Hahn, Ph. Furtwängler, J. Radon, K. Mayrhofer, N. Hofreiter, H. Reiter, K. Sigmund, J. Cigler.
The journal is devoted to research in mathematics in its broadest sense. Over the years, it has attracted a remarkable cast of authors, ranging from G. Peano, and A. Tauber to P. Erdös and B. L. van der Waerden. The volumes of the Monatshefte contain historical achievements in analysis (L. Bieberbach, H. Hahn, E. Helly, R. Nevanlinna, J. Radon, F. Riesz, W. Wirtinger), topology (K. Menger, K. Kuratowski, L. Vietoris, K. Reidemeister), and number theory (F. Mertens, Ph. Furtwängler, E. Hlawka, E. Landau). It also published landmark contributions by physicists such as M. Planck and W. Heisenberg and by philosophers such as R. Carnap and F. Waismann. In particular, the journal played a seminal role in analyzing the foundations of mathematics (L. E. J. Brouwer, A. Tarski and K. Gödel).
The journal publishes research papers of general interest in all areas of mathematics. Surveys of significant developments in the fields of pure and applied mathematics and mathematical physics may be occasionally included.