Special geometry in dimensions 6,7,8 is a vibrant research area comprising a global community of researchers, and is greatly inspired by developments in mathematical physics. The field brings together diverse techniques and perspectives from differential geometry, algebraic geometry, gauge theory, geometric analysis, topology, homotopy theory, string theory and gravity. In particular, the analytic approaches that have been successfully applied include both elliptic methods (such as glueing constructions) and parabolic methods (geometric evolution equations). By combining this wide variety of methods, the field has seen important progress in recent years on a number of fronts, including on constructing examples and key steps towards various conjectures and open problems stemming from the celebrated Donaldson-Thomas programme. This programme aims to construct enumerative and gauge-theoretic invariants in dimensions 6,7,8 that generalize the analogous theories in dimensions 2,3,4 that were enormously influential in the development of geometry and topology in the 1980s and 1990s (such as Gromov-Witten invariants from symplectic topology, Floer homology of 3-manifold, and Donaldson and Seiberg-Witten invariants of 4-dimensional gauge theories.) The study of the moduli space of holonomy G2 metrics using analytic invariants is another important recent breakthrough, as was the analysis of adiabatic limits of coassociative fibrations.

 

However, many major challenges remain, particularly in concretely realising geometry problems arising via considerations from physics, as well as in the fundamental existence questions pertaining to special geometries. For example, the Hull-Strominger system for non-Kahler Calabi-Yau manifolds, and the analogous heterotic G2 system in 7 dimensions are extremely active areas of current research closely connecting mathematicians and physicists. Moreover, recent research and workshops in the field have demonstrated that there are many new avenues that have yet to be explored, which will provide new insight and have the potential to lead to significant progress in the area.