WITH a string of talks and op-ed columns, Larry Summers has revived discussion in the "secular stagnation" hypothesis. Income has become concentrated in the hands of groups, like reserve-accumulating foreign governments and the rich, with low propensities to consume, the thinking goes. That has generated excess saving and pushed down real interest rates until they are substantially negative at many durations. That, in turn, has made life very difficult for central banks, which have struggled to stoke up adequate demand with nominal interest rates wedged up against zero. Mr Summers identifies three broad solutions ... (full story)