US 9,170,489 B2  102  101  -continued  (Allb)  Ric  R$_{3}$c  (Alie)  Repeating unit (b) may be a repeating unit having a lactone  structure as the polar group.  The specific examples of repeating units having a hydroxyl  group or a cyano group are shown below but the invention is  not restricted thereto.  R$_{2}$c, R$_{3}$c and R$_{4}$c respectively have the same meaning with  R$_{2}$c, R$_{3}$c and R$_{4}$c in formulae (VIIa) to (VIIc).  In formulae (Alla) to (AIIc), R$_{1}$c represents a hydrogen  atom, a methyl group, a trifluoromethyl group or ahydroxym› ethyl group.  -continued  ~  OH  OH  OH  OH  ~H  0  0  OH  OH  ~  HO  HO 