This article studies the geometry of moduli spaces of
G2-manifolds, associative cycles, coassociative cycles and
deformed Donaldson–Thomas bundles. We introduce natural symmetric cubic tensors
and differential forms on these moduli spaces. They correspond to Yukawa
couplings and correlation functions in M-theory.
¶ We expect that the Yukawa coupling characterizes (co-)associative fibrations on
these manifolds. We discuss the Fourier transformation along such fibrations and
the analog of the Strominger–Yau–Zaslow mirror conjecture for
G2-manifolds.
¶ We also discuss similar structures and transformations for Spin(7)-
manifolds.