Perhaps you should try some spelling variations:
deepening inequality » explaining inequality, earnings inequality, measuring inequality
widening inequality » reducing inequality, rising inequality, fighting inequality
learning inequality » earnings inequality, learning quality, garding inequality
hardy inequality » hardy's inequality, hardy inequalities, harnack inequality
wage » wave

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: wage AND ((((widening inequality) OR (deepening inequality))) OR (((learning inequality) OR (hardy inequality)))).
• Adding a wildcard symbol may retrieve word variants: wage and ((((widening inequality) or (deepening inequality))) or (((learning inequality) or (hardy inequality))))*.