The paper studies the class $\cal D$ of $r$-generic sets in the sense of {\it M. Dowd} [Inf.~Comput.~96, No.~1, 65‒76 (1992; Zbl 0755.68052)]. The following results are given: { indent=6.5mm \item{(a)} $\cal D$ is closed under independent bounded truth-table reductions, that is, bounded truth-table reductions that for different arguments produce disjoint sets of oracle queries and use only Boolean onto functions as truth tables. \item{(b)} (an immediate consequence of the above) $\cal D$ is closed under reductions computed by sequences of Boolean alternating AND-OR circuits (for some reason called Boolean decision trees in the paper). \item{(c)} Every Martin-Löf random sequence is in $\cal D$. However, the class of Martin-Löf random sets (as well as the class of weak Martin-Löf random sets) is not closed under the reductions used in (b) above. }
Reviewer: Heribert Vollmer (Hannover)