A compound represented by a formula (IIa) is provided. In formula (IIa), Y1 to Y8 represent —O—, —S—, —O—C(═O)—, —C(═O)—O— or the like, G1 and G2 represent a divalent linear aliphatic group having 1 to 20 carbon atoms or the like, Z1 and Z2 represent an alkenyl group having 2 to 10 carbon atoms or the like, Ax represents a group represented by a formula (II), wherein X represents an oxygen atom, a sulfur atom or the like, D represents an alkylene group having 1 to 20 carbon atoms or the like, A1 represents a trivalent aromatic group or the like, A2 and A3 represent a divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms or the like, A4 and A5 represent a divalent aromatic group having 4 to 30 carbon atoms or the like, Q1 represents an alkyl group having 1 to 6 carbon atoms or the like, and m and n are 0 or 1.