On the formality problem for manifolds with special holonomy

In sections 1 and 2 we follow our online talk at the 21st Geometrical Seminar (Beograd, Serbia) on June 30, 2022 by giving a survey of the formality problem for manifold with special holonomy and exposing recent results by M. Amann and the author on the formality of Joyce’s examples of G_2-manifolds. In section 3 we expose the approach to establishing the formality by using the intersection Massey products.