“…Distributed algorithms dealing with problem (1) have been studied extensively in the literature [56,36,37,28,19,20,52,13,46,34,45]. Recently, there has been considerable interest in distributed implementation of stochastic gradient algorithms [48,54,14,3,5,55,6,9,10,7,32,24,26,40,51,41,18]. The literature has shown that distributed methods may compete with, or even outperform, their centralized counterparts under certain conditions [9,10,26,40,41].…”