{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,10]],"date-time":"2026-04-10T16:26:12Z","timestamp":1775838372812,"version":"3.50.1"},"reference-count":21,"publisher":"Cambridge University Press (CUP)","issue":"2","license":[{"start":{"date-parts":[[2014,3,12]],"date-time":"2014-03-12T00:00:00Z","timestamp":1394582400000},"content-version":"unspecified","delay-in-days":15990,"URL":"https:\/\/www.cambridge.org\/core\/terms"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. symb. log."],"published-print":{"date-parts":[[1970,6]]},"abstract":"<jats:p>The first of this sequence of papers [21] surveyed the progress that has been made in embedding partially ordered sets as initial segments of the uncountable upper semilattice <jats:bold>D<\/jats:bold> of degrees of unsolvability. The principal concern of the present and subsequent parts will be with initial segments of the countable upper semilattice <jats:bold>D<\/jats:bold> (\u2266<jats:bold>0<\/jats:bold><jats:sup>(1)<\/jats:sup>) of degrees \u2266<jats:bold>0<\/jats:bold><jats:sup>(1)<\/jats:sup>; a summary appeared in [21].<\/jats:p>","DOI":"10.2307\/2270517","type":"journal-article","created":{"date-parts":[[2006,5,6]],"date-time":"2006-05-06T17:00:41Z","timestamp":1146934841000},"page":"243-266","source":"Crossref","is-referenced-by-count":18,"title":["Initial segments of the degrees of unsolvability Part II: minimal degrees"],"prefix":"10.1017","volume":"35","author":[{"given":"C. E. 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