On extremal transitions of Calabi-Yau threefolds and the singularity of the associated 7-space from rolling

Volker Braun, Chien-Hao Liu

M-theory compactification leads one to consider 7-manifolds obtained by rolling Calabi-Yau threefolds in the web of Calabi-Yau moduli spaces. The resulting 7-space in general has s…