Abstract:
We study here the degree-theoretic structure of set-theoretical splittings of recursively enumerable
(r.e.) sets into differences of r.e. sets. As a corollary we deduce that the ordering of wtt-degrees
of unsolvability of differences of r.e. sets is not a distributive semilattice and is not elementarily
equivalent to the ordering of r.e. wtt-degrees of unsolvability.