2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/55498At low energy the near horizon geometry of nonextreme black holes in four dimensions exhibits an effective SL(2,R)_L x SL(2,R)_R symmetry. The parameters of the corresponding induced conformal field theory gives the correct expression for the black hole entropy. The resulting spectrum of the Schwarzchild black hole is compared with another proposal.8 pages, latex, uses sprocl.styHigh Energy Physics - TheoryGeneral Relativity and Quantum Cosmologytext