a^{a0}_{c0} b^{a2}_{c1} c^{c1,a1}_{a3,v0} eta1^{a3}_{a2} a+(c0) a+(v0) a-(a1) a-(a0)
-a^{a2}_{c0} b^{a0}_{c1} c^{c1,a1}_{a3,v0} eta1^{a3}_{a2} a+(c0) a+(v0) a-(a1) a-(a0)
-a^{a0}_{c1} b^{a2}_{c0} c^{c1,a1}_{a3,v0} eta1^{a3}_{a2} a+(c0) a+(v0) a-(a1) a-(a0)
+a^{a2}_{c1} b^{a0}_{c0} c^{c1,a1}_{a3,v0} eta1^{a3}_{a2} a+(c0) a+(v0) a-(a1) a-(a0)