“…(1. 1) Subsequent improvements, first by Lucier [15], and most recently by Ruzsa and Sanders [17], show that the function on the right hand side in the conclusion (1.1) may be replaced by exp(−c(log x) 1/4 ), for some positive absolute constant c. Problems in which one asks for specified constellations of differences between successive terms from a sequence of elements in E, each difference depending on the same shifted prime, have been addressed only very recently. Thus, for example, the problem of exhibiting non-trivial three term arithmetic progressions from E, with common difference a shifted prime, was successfully analysed by Frantzikinakis, Host and Kra [5], with the analogous problem for longer arithmetic progressions conditional on the Inverse Conjecture for Gowers Norms formulated by Green and Tao [8].…”