SORRY
For the following publication, no online-version is available.

M. Kummer, F. Stephan. Weakly semirecursive sets and r.e. orderings.
C. Jockusch, F. Stephan. A cohesive set which is not high.
M. Kummer, F. Stephan. Some aspects of frequency computation.
F. Stephan. X-Raeume als Verallgemeinerung topologischer Raeume.
R. Beigel, W. Gasarch, M. Kummer, G. Martin, T. McNicholl, F. Stephan.
   The complexity of Odd(A,n). Please check out the corresponding
   conference-version "On the query complexity of sets."

The Zentralblatt fuer Mathematik gives for the first two the
following reviews.

767.03023
Kummer, Martin; Stephan, Frank
Weakly semirecursive sets and r.e. orderings. (English)
[J] Ann. Pure Appl. Logic 60, No.2, 133-150 (1993). [ISSN 0168-0072]

This paper continues the investigation of weakly semirecursive sets
-- introduced by C. G. Jockush jun. and J. C. Owings [J. Symb. Logic 55,
637-644 (1990; Zbl. 702.03020)] -- using methods from the theory
of r.e. partial orderings. For instance, they prove that a set is
weakly semirecursive if only if it is an initial segment of an r.e.
partial ordering (this result generalizes the Appel-McLaughlin
Theorem for semirecursive sets).
[ C.Calude (Auckland) ]

MSC 1991: 
       03D25 Recursively enumerable sets
       03D30 Degrees, other than r.e.
       03D35 Undecidability

Keywords: weakly semirecursive sets; r.e. partial orderings; initial segment

799.03048
Jockusch, Carl; Stephan, Frank
A cohesive set which is not high. (English)
[J] Math. Log. Q. 39, No.4, 515-530 (1993); correction ibid. 43, 569
(1997). [ISSN 0942-5616]

We study the degrees of unsolvability of sets which are cohesive (or
have weaker recursion-theoretic ``smallness'' properties). We answer
a question raised by the first author in 1972 by showing that there is
a cohesive set A whose degree a satisfies a'' = 0'' and hence it not high.
We characterize the jumps of the degrees of r-cohesive sets and we show
that the degrees of r-cohesive sets coincide with those of the cohesive
sets. We obtain analogous results for strongly hyperimmune and strongly
hyperhyperimmune sets in the place of r-cohesive and cohesive
sets respectively. We show that every strongly hyperimmune set
whose degree contains either a Boolean combination of Sigma 2
sets or a 1-generic set is of high degree. We also study primitive
recursive analogues of these notions and in this case we characterize
the corresponding degrees exactly.
[ F.Stephan (Karlsruhe) ]

MSC 1991: 
       03D30 Degrees, other than r.e.
       03D55 Hierarchies

Keywords: maximal set; degrees of unsolvability; cohesive set;
jumps; strongly hyperhyperimmune sets; strongly hyperimmune set;
primitive recursive analogues