Relation Between Holonomy Groups in Superstrings, M and F-theories

We consider manifolds with special holonomy groups SU(3), G2 and Spin(7) as suitable for compactification of superstrings, M-theory and F-theory (with only one time) respectively. The relations of these groups with the octonions are discussed, reinforcing their role in the physics of string theory and duality. We also exhibit three triple exact sequences explaining the connections between the mentioned special holonomy groups.