Toward Understanding Exclusive Read

The ability of many processors to simultaneously read from the same cell of shared memory can give additional power to a parallel random access machine. In this paper, a natural Boolean function of n variables is described, and it is shown that the expected running time of any probabilistic EROW PRAM computing this function is in $\Omega (\sqrt {\log n} )$, although it can be computed by a CROW PRAM in $O(\log \log n)$ steps.