Aspinwall, PS; Horja, RP; Karp, RL, *Massless D-branes on Calabi-Yau threefolds and monodromy*,
Communications in Mathematical Physics, vol. 259 no. 1
(2005),
pp. 45-69 [hep-th/0209161], [doi] .
**Abstract:**

*We analyze the link between the occurrence of massless B-type D-branes for specific values of moduli and monodromy around such points in the moduli space. This allows us to propose a classification of all massless B-type D-branes at any point in the moduli space of Calabi-Yau's. This classification then justifies a previous conjecture due to Horja for the general form of monodromy. Our analysis is based on using monodromies around points in moduli space where a single D-brane becomes massless to generate monodromies around points where an infinite number become massless. We discuss the various possibilities within the classification. © Springer-Verlag 2005.*