Annals of Mathematical LogicVolume 4, Issue 1, March 1972, Pages 31-73Degrees of unsolvability complementary between recursively enumerable degrees, Part 1Author links open overlay panelS.B. CooperShow moreShareCitehttps://doi.org/10.1016/0003-4843(72)90011-3Get rights and contentUnder an Elsevier user licenseopen archivePrevious article in issueNext article in issueRecommended articlesCited by (0)Copyright © 1972 Published by Elsevier B.V.