Ooguri, HirosiVafa, Cumrun2019-09-221996Ooguri, Hirosi, and Cumrun Vafa. 1996. “Two-Dimensional Black Hole and Singularities of CY Manifolds.” Nuclear Physics B 463 (1): 55–72. https://doi.org/10.1016/0550-3213(96)00008-9.0169-68230550-32131873-1562http://nrs.harvard.edu/urn-3:HUL.InstRepos:41385071We study the degenerating limits of superconformal theories for compactifications on singular K3 and Calabi-Yau threefolds. We find that in both cases the degeneration involves creating an Euclidean two-dimensional black hole coupled weakly to the rest of the system. Moreover we find that the conformal theory of A(n) singularities of K3 are the same as that of the symmetric fivebrane. We also find intriguing connections between ADE (1,n) non-critical strings and singular limits of superconformal theories on the corresponding ALE space.en-USJournal Article2019-09-2210.1016/0550-3213(96)00008-9