{"corpus_id":250904081,"paper_sha":"080c1e8b41755c3bce3675fc605c5f3f05a2801e","doi":"10.1088/0264-9381/14/4/002","arxiv_id":"gr-qc/9702052","pmid":null,"pmcid":null,"mag_id":2098169780,"dblp_id":null,"acl_id":null,"title":"On the dimensionality of spacetime","year":1997,"publication_date":"1997-02-25","venue":"","journal":{"name":"Classical and Quantum Gravity","pages":"L69 - L75","volume":"14"},"journal_issn":null,"journal_title":null,"publication_types":[],"pubmed_pub_types":null,"s2_fields_of_study":["Physics"],"reference_count":25,"citation_count":69,"influential_citation_count":1,"is_open_access":true,"arxiv_categories":["gr-qc","hep-ph","hep-th"],"arxiv_license":null,"arxiv_journal_ref":"Class.Quant.Grav.14:L69-L75,1997","mesh_headings":null,"chemicals":null,"comments_corrections":null,"source_flags":1,"s2_open_access_pdf_url":"https://arxiv.org/pdf/gr-qc/9702052","s2_open_access_landing_url":"https://www.semanticscholar.org/paper/080c1e8b41755c3bce3675fc605c5f3f05a2801e","s2_open_access_license":null,"s2_open_access_status":"GREEN","pmc_open_access_pdf_url":null,"pmc_open_access_landing_url":null,"pmc_open_access_license":null,"pmc_open_access_status":null,"unpaywall_open_access_pdf_url":null,"unpaywall_open_access_landing_url":null,"unpaywall_open_access_license":null,"unpaywall_open_access_status":null,"abstract":"Some superstring theories have more than one effective low-energy limit corresponding to classical spacetimes with different dimensionalities. We argue that all but the (3 + 1)-dimensional one might correspond to `dead worlds', devoid of observers, in which case all such ensemble theories would actually predict that we should find ourselves inhabiting a (3 + 1)-dimensional spacetime. With more or less than one time dimension, the partial differential equations of nature would lack the hyperbolicity property that enables observers to make predictions. In a space with more than three dimensions, there can be no traditional atoms and perhaps no stable structures. A space with less than three dimensions allows no gravitational force and may be too simple and barren to contain observers.","claims":[{"public_id":"cl_583cf42de5585c0798afaa7f0a475681","status":"active","text":"Among the low-energy spacetime dimensionalities arising in some superstring theories, only the (3 + 1)-dimensional case is argued to be compatible with observers.","confidence":0.95,"contributors":[{"id":1,"public_id":"12632b8b5f","public_label":"Anonymous (12632b8b5f)","roles":["extraction"],"url":"https://sah.borca.ai/u/12632b8b5f"}],"url":"https://sah.borca.ai/claims/cl_583cf42de5585c0798afaa7f0a475681"},{"public_id":"cl_6a9b85bc6512fec44accad14da2f26e9","status":"active","text":"Spacetimes with fewer than three spatial dimensions are argued to allow no gravitational force and to be too simple and barren to contain observers.","confidence":0.9,"contributors":[{"id":1,"public_id":"12632b8b5f","public_label":"Anonymous 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