{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,20]],"date-time":"2026-08-20T12:29:53Z","timestamp":1787228993098,"version":"build-2736575974"},"reference-count":25,"publisher":"Society for Industrial & Applied Mathematics (SIAM)","issue":"1","funder":[{"DOI":"10.13039\/501100010751","name":"Fondo Nacional de Desarrollo Cient\u00edfico, Tecnol\u00f3gico y de Innovaci\u00f3n Tecnol\u00f3gica","doi-asserted-by":"publisher","award":["2022-1D2-091"],"award-info":[{"award-number":["2022-1D2-091"]}],"id":[{"id":"10.13039\/501100010751","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["SIAM J. Appl. Dyn. Syst."],"published-print":{"date-parts":[[2025,3,31]]},"abstract":"<jats:p>Abstract.<\/jats:p>\n                  <jats:p>We investigate the integrability of an anisotropic universe with matter and cosmological constant formulated as Bianchi IX models. The presence of the cosmological constant causes the existence of a critical point in the finite part of the phase space. The separatrix associated to Einstein\u2019s static universe is entirely contained in an invariant isotropic plane forgetting the singularity at the origin. This invariant plane of isotropy is an integrable subspace of the Taub type. In this paper we analyse the differential Galois group of the second order variational equations to this plane in order to apply the integrability theorem of the second author with Ramis and Sim\u00f3. The main result is that the model is nonintegrable by meromorphic functions.<\/jats:p>","DOI":"10.1137\/23m1623070","type":"journal-article","created":{"date-parts":[[2025,3,13]],"date-time":"2025-03-13T04:00:43Z","timestamp":1741838443000},"page":"815-835","source":"Crossref","is-referenced-by-count":0,"title":["Nonintegrability of the Axisymmetric Bianchi IX Cosmological Model via Differential Galois Theory"],"prefix":"10.1137","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5627-4188","authenticated-orcid":true,"given":"Primitivo. B.","family":"Acosta-Hum\u00e1nez","sequence":"first","affiliation":[{"name":"Universidad Aut\u00f3noma de Santo Domingo, Santo Domingo 10105, Dominican Republic."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Juan. J.","family":"Morales-Ruiz","sequence":"additional","affiliation":[{"name":"Universidad Polit\u00e9cnica de Madrid, 28040 Madrid, Spain."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"T. J.","family":"Stuchi","sequence":"additional","affiliation":[{"name":"Universidade Federale de Rio de Janeiro, Rio de Janeiro, 21941-853, Brazil."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"351","published-online":{"date-parts":[[2025,3,13]]},"reference":[{"key":"ref1","volume-title":"Handbook of Mathematical Functions: With Formulas, Graphs and Mathematical Tables","author":"Abramowitz M.","year":"1965"},{"key":"ref2","doi-asserted-by":"publisher","DOI":"10.3934\/dcdsb.2008.10.265"},{"key":"ref3","doi-asserted-by":"publisher","DOI":"10.1016\/j.jde.2018.02.016"},{"key":"ref4","doi-asserted-by":"publisher","DOI":"10.1016\/S0034-4877(11)60019-0"},{"key":"ref5","first-page":"088","volume":"2019","author":"Acosta-Hum\u00e1nez P. B.","year":"2019","journal-title":"Symmetry Integr. Geom. 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Calzetta, Homoclinic Chaos in Relativistic Cosmology in Deterministic Chaos in General Relativity, Springer, New York, 1994, pp. 203\u2013235, https:\/\/doi.org\/10.1007\/978-1-4757-9993-4_12.","DOI":"10.1007\/978-1-4757-9993-4_12"},{"key":"ref12","doi-asserted-by":"publisher","DOI":"10.1103\/PhysRevLett.78.998"},{"key":"ref13","doi-asserted-by":"publisher","DOI":"10.1090\/gsm\/122"},{"key":"ref14","doi-asserted-by":"publisher","DOI":"10.1103\/PhysRevD.56.730"},{"key":"ref15","doi-asserted-by":"publisher","DOI":"10.1007\/BF00759025"},{"key":"ref16","volume-title":"Linear Algebraic Groups","author":"Humphreys J.","year":"2012"},{"key":"ref17","doi-asserted-by":"publisher","DOI":"10.1016\/S0747-7171(86)80010-4"},{"key":"ref18","doi-asserted-by":"publisher","DOI":"10.1103\/PhysRevLett.22.1071"},{"key":"ref19","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-0348-0723-4"},{"key":"ref20","doi-asserted-by":"publisher","DOI":"10.4310\/MAA.2001.v8.n1.a3"},{"key":"ref21","doi-asserted-by":"publisher","DOI":"10.4310\/MAA.2001.v8.n1.a4"},{"key":"ref22","doi-asserted-by":"publisher","DOI":"10.1016\/j.ansens.2007.09.002"},{"key":"ref23","doi-asserted-by":"publisher","DOI":"10.1103\/PhysRevD.72.083516"},{"key":"ref24","doi-asserted-by":"publisher","DOI":"10.2307\/1969567"},{"key":"ref25","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-642-55750-7"}],"container-title":["SIAM Journal on Applied Dynamical Systems"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/epubs.siam.org\/doi\/pdf\/10.1137\/23M1623070","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,20]],"date-time":"2026-08-20T12:11:40Z","timestamp":1787227900000},"score":1,"resource":{"primary":{"URL":"https:\/\/epubs.siam.org\/doi\/10.1137\/23M1623070"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,3,13]]},"references-count":25,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2025,3,31]]}},"alternative-id":["10.1137\/23M1623070"],"URL":"https:\/\/doi.org\/10.1137\/23m1623070","relation":{},"ISSN":["1536-0040"],"issn-type":[{"value":"1536-0040","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,3,13]]}}}