equation icon  @aBac + eeadEcexad + eecdEaexad = 0, (52) a e ad e ad @ Eac - eeadBc x - eecdBa x = 0, (53) @Ebc + eae(b@aBec) + 2xEbc - 2xa(bEc)a + hbcEadxad - Ea(bxc)a + 2eea(bBec)xa = 0, (54) a e a ad a e a @Bbc - eae(b@ E c) + 2xBbc - 2x (bBc)a + hbcBadx - Ba(bxc) - 2eea(bE c)x = 0. (55)