The debate was, as you probably know, initiated by Larry Summers, who put forward the secular stagnation hypothesis.
3 The focus of the discussion among scholars, policy makers, and market commentators is (a) whether the lower equilibrium interest rate is a permanent phenomenon;  1  K. Fukao, T. Miyagawa, H. K. Pyo, and K. H. Rhee (2012), “Estimates of Total Factor Productivity, the Contribution of ICT, and Resource Reallocation Effects in Japan and Korea,” in M. Mas and R. Stehrer (eds.