The undecidability of the Π4-theory for the r.e. wtt and Turing degrees

Publisher: Cambridge University Press

E-ISSN: 1943-5886|60|4|1118-1136

ISSN: 0022-4812

Source: The Journal of Symbolic Logic, Vol.60, Iss.4, 1995-12, pp. : 1118-1136

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Abstract

We show that the Π4-theory of the partial order of recursively enumerable weak truth-table degrees is undecidable, and give a new proof of the similar fact for r.e. T-degrees. This is accomplished by introducing a new coding scheme which consists in defining the class of finite bipartite graphs with parameters.