2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/55973The M(atrix) model has a dual realization as IIA superstring theory in the near-horizon geometry of the supergravity D0-brane. The role of $adS_2$ in this correspondence is reviewed, and some aspects of holography that it suggests are discussed.9 pp. Latex. Revised to include corrections, improvements and additional references. To appear in Proceedings of the 3'rd Puri workshop on Quantum Field Theory, Quantum Gravity and Strings, Puri, Orissa, India, December 9-19, 1998High Energy Physics - Theorytext