Israel Journal of Mathematics

, Volume 26, Issue 1, pp 91–94 | Cite as

Fixed points of jump preserving automorphisms of degrees

  • Carl G. Jockusch
  • Robert M. Solovay


It is shown that any jump preserving order automorphismF of the degrees of unsolvability must satisfyF(c) = c for all degreesc≧0 (4) . The proof uses a result on initial segments of degrees in combination with an iteration of the Friedberg completeness criterion.


Distributive Lattice Initial Segment Direct Appeal WATSON Research Infinite Domain 


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Copyright information

© Hebrew University 1977

Authors and Affiliations

  • Carl G. Jockusch
    • 1
    • 2
  • Robert M. Solovay
    • 1
    • 2
  1. 1.University of Illinois at Urbana-ChampaignUSA
  2. 2.I.B.M. T. J. Watson Research CenterUSA

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