Negative Curvature

          @misc{ pirsa_PIRSA:07060077,
            doi = {10.48660/07060077},
            url = {https://pirsa.org/07060077},
            author = {Susskind, Leonard},
            keywords = {Quantum Fields and Strings, Particle Physics, Cosmology},
            language = {en},
            title = {Negative Curvature},
            publisher = {Perimeter Institute},
            year = {2008},
            month = {jun},
            note = {PIRSA:07060077 see, \url{https://pirsa.org}}
          }