caa a22 4500 388039450 CHVBK 20180307125017.0 cr unu---uuuuu 161130e199806 xx s 000 0 eng 10.2307/2586839 doi S0022481200014973 pii (NATIONALLICENCE)cambridge-10.2307/2586839 Relative enumerability in the difference hierarchy [Elektronische Daten] We show that the intersection of the class of 2-REA degrees with that of the ω-r.e. degrees consists precisely of the class of d.r.e. degrees. We also include some applications and show that there is no natural generalization of this result to higher levels of the REA hierarchy. Copyright © Association for Symbolic Logic 1998 Arslanov Marat M. 13 Karbishev St. No. 109, Kazan 420087, Russia, E-mail: marat@ksu.ru Laforte Geoffrey L. Institute for Human and Machine Cognition, University of West Florida, 11000 University Parkway, Pensacola, FL 32514, USA, E-mail: glaforte@coginst.uwf.edu Slaman Theodore A. Department of Mathematics, The University of California, Berkeley, CA 94720-3840, USA, E-mail: slaman@math.berkeley.edu The Journal of Symbolic Logic Cambridge University Press 63/2(1998-06), 411-420 0022-4812 63:2<411 1998 63 JSL https://doi.org/10.2307/2586839 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.2307/2586839 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Arslanov Marat M. 13 Karbishev St. No. 109, Kazan 420087, Russia, E-mail: marat@ksu.ru NATIONALLICENCE 700 1- Laforte Geoffrey L. Institute for Human and Machine Cognition, University of West Florida, 11000 University Parkway, Pensacola, FL 32514, USA, E-mail: glaforte@coginst.uwf.edu NATIONALLICENCE 700 1- Slaman Theodore A. Department of Mathematics, The University of California, Berkeley, CA 94720-3840, USA, E-mail: slaman@math.berkeley.edu NATIONALLICENCE 773 0- The Journal of Symbolic Logic Cambridge University Press 63/2(1998-06), 411-420 0022-4812 63:2<411 1998 63 JSL CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge