terms whereas bls and els contain only linear a, b, c, d and no degree zero terms. Differentiating rs once we obtain (i)/ biscos — hose's + O(w) irs kw/ — cis +O(w) (2.52) EFTA00748903 ITS Chapter 2: Strategy selection in structured populations 37 We want to show the linearity of 4 ) which is 4