-continued  described above for the substituent which the polycyclic  aliphatic hydrocarbon structure may have.  The position of substitution of  -O-Y-X$_{2 }$ in the gen› eral formula ( 4) may be the para-position, the meta-position,  or the ortho-position with respect to the bonding position of  a benzene ring to a polymer main chain, but, and the  para-position is preferred.  In the present invention, the repeating unit represented by  the general formula (3) described above is most preferably  a repeating unit represented by the following general for› mula (4’).  [Chem. 28]  47  US 9,958,775 B2  48  In the general formula (4’), R$_{13 }$ represents a hydrogen  atom or a methyl group.  In the general formula (4’), R$_{13 }$ represents a hydrogen  atom or a methyl group, but a hydrogen atom is particularly  preferred.  Specific examples of the repeating unit shown by the  general formula (3) include the following.  The position of substitution of an adamantyl ester group 35  in the general formula (4’) may be the para-position, the  meta-position, or the ortho-position with respect to the  bonding position of a benzene ring to a polymer main chain,  but, and the para-position is preferred.  [Chem. 29]  (4’) 