Quasilocal energy for stationary axisymmetric EMDA black hole

By using Brown-York quasilocal energy theory we calculate the quasilocal en ergy of a stationary axisymmetic EMDA black hole and explore the universali ty of Martinet's conjecture in string theory. We show that the energy is po sitive and monotonically decreases to the ADM mass at spatial infinity, and the Martinet's conjecture, the Brown-York quasilocal energy at the outer h orizon reduces to twice its irreducible mass, is still valid for stationary axisymmetric EMDA black hole. From the result we also find that the Kerr-S en spacetime keeps up with Martinet's conjecture. This is different from th e Bose-Naing result that the quasilocal energy of the Kerr-Sen spacetime do es not approach the Martinet's conjecture.