Suppose that the Phillips curve is given by:

_t - _t^e = 0.09 + 0.12m - 3u_t

where m is the markup of prices over wages. Suppose the m is initially equal to 25%, but that as a result of a sharp increase in oil prices, m increases to 50% in year t and after.

1. Why would an increase in oil prices result in an increase in m?
2. What is the long run effect of the increase in m on the natural rate of unemployment?