Ooguri, HirosiVafa, Cumrun2019-09-221997Ooguri, Hirosi, and Cumrun Vafa. 1997. “Geometry of N = 1 Dualities in Four Dimensions.” Nuclear Physics B 500 (1–3): 62–74. https://doi.org/10.1016/s0550-3213(97)00304-0.0169-68230550-32131873-1562http://nrs.harvard.edu/urn-3:HUL.InstRepos:41385074We discuss how N = 1 dualities in four dimensions are geometrically realized by wrapping D-branes about 3-cycles of Calabi-Yau threefolds. In this setup the N = 1 dualities for SU, SO and USp gauge groups with fundamental fields gee mapped to statements about the monodromy and relations among 3-cycles of Calabi-Yau threefolds. The connection between the theory and its dual requires passing through configurations which are T-dual to the well-known phenomenon of decay of BPS states in N = 2 field theories in four dimensions. We compare our approach to recent works based on configurations of D-branes in the presence of NS 5-branes and give simple classical geometric derivations of various exotic dynamics involving D-branes ending on NS branes.en-USJournal Article2019-09-2210.1016/S0550-3213(97)00304-0