1. Heinrich Rolletschek (1995). Some New Lattice Constructions in High R. E. Degrees. Mathematical Logic Quarterly 41 (3):395-430.
    A well-known theorem by Martin asserts that the degrees of maximal sets are precisely the high recursively enumerable degrees, and the same is true with ‘maximal’ replaced by ‘dense simple’, ‘r-maximal’, ‘strongly hypersimple’ or ‘finitely strongly hypersimple’. Many other constructions can also be carried out in any given high r. e. degree, for instance r-maximal or hyperhypersimple sets without maximal supersets . In this paper questions of this type are considered systematically. Ultimately it is shown that every conjunction of simplicity- (...)
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  2. Heinrich Rolletschek (1993). A Variant of the Notion of Semicreative Set. Mathematical Logic Quarterly 39 (1):33-46.
    This paper introduces the notion of cW10-creative set, which strengthens that of semicreative set in a similar way as complete creativity strengthens creativity. Two results are proven, both of which imply that not all semicreative sets are cW10-creative. First, it is shown that semicreative Dedekind cuts cannot be cW10-creative; the existence of semicreative Dedekind cuts was shown by Soare. Secondly, it is shown that if A ⊕ B, the join of A and B, is cW10-creative, then either A or B (...)
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  3. Heinrich Rolletschek (1983). Closure Properties of Almost-Finiteness Classes in Recursive Function Theory. Journal of Symbolic Logic 48 (3):756-763.
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