{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2022,3,31]],"date-time":"2022-03-31T13:35:32Z","timestamp":1648733732805},"reference-count":6,"publisher":"Cambridge University Press (CUP)","issue":"3","license":[{"start":{"date-parts":[[2014,3,12]],"date-time":"2014-03-12T00:00:00Z","timestamp":1394582400000},"content-version":"unspecified","delay-in-days":18455,"URL":"https:\/\/www.cambridge.org\/core\/terms"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. symb. log."],"published-print":{"date-parts":[[1963,9]]},"abstract":"<jats:p>This paper answers negatively the chief remaining open questions concerning the separation properties of first-order prefix classes of structures (discussed by Addison [2], pp. 26\u201337).<\/jats:p><jats:p><jats:bold>1. Preliminaries.<\/jats:bold> The first and second separation properties and the reduction property are defined for arbitrary classes of subsets of an arbitrary set.<\/jats:p>","DOI":"10.2307\/2271068","type":"journal-article","created":{"date-parts":[[2006,5,6]],"date-time":"2006-05-06T20:21:59Z","timestamp":1146946919000},"page":"222-236","source":"Crossref","is-referenced-by-count":3,"title":["Separation principles in the hierarchy theory of pure first-order logic"],"prefix":"10.1017","volume":"28","author":[{"given":"M. R.","family":"Krom","sequence":"first","affiliation":[]}],"member":"56","published-online":{"date-parts":[[2014,3,12]]},"reference":[{"key":"S0022481200117967_ref006","first-page":"84","article-title":"Arithmetical extensions of relational systems","volume":"13","author":"Tarski","year":"1957","journal-title":"Compositio Mathematica"},{"key":"S0022481200117967_ref003","doi-asserted-by":"publisher","DOI":"10.1090\/pspum\/005\/0141599"},{"key":"S0022481200117967_ref002","first-page":"26","article-title":"The theory of hierarchies","author":"Addison","year":"1962","journal-title":"Logic, methodology and philosophy of science"},{"key":"S0022481200117967_ref001","doi-asserted-by":"publisher","DOI":"10.4064\/fm-46-2-123-135"},{"key":"S0022481200117967_ref005","volume-title":"Introduction to metamathematics","author":"Kleene","year":"1952"},{"key":"S0022481200117967_ref004","first-page":"250","article-title":"Linear reasoning. A new form of the Herbrand-Gentzen theorem","volume":"22","author":"Craig","year":"1957","journal-title":"this Journal"}],"container-title":["Journal of Symbolic Logic"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.cambridge.org\/core\/services\/aop-cambridge-core\/content\/view\/S0022481200117967","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2019,6,4]],"date-time":"2019-06-04T19:16:08Z","timestamp":1559675768000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.cambridge.org\/core\/product\/identifier\/S0022481200117967\/type\/journal_article"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1963,9]]},"references-count":6,"journal-issue":{"issue":"3","published-print":{"date-parts":[[1963,9]]}},"alternative-id":["S0022481200117967"],"URL":"https:\/\/doi.org\/10.2307\/2271068","relation":{},"ISSN":["0022-4812","1943-5886"],"issn-type":[{"value":"0022-4812","type":"print"},{"value":"1943-5886","type":"electronic"}],"subject":[],"published":{"date-parts":[[1963,9]]}}}