Solvability of the Hull–Strominger Bianchi identity through conifold transitions

Establish whether the Bianchi identity of the Hull–Strominger system can be solved through conifold transitions between complex manifolds with trivial canonical bundle.

Background

The Hull–Strominger system couples a Hermitian metric and its torsion to an exact four-form source produced by an instanton. In the setting of conifold transitions, the central unresolved issue is whether this Bianchi identity can be solved compatibly with the transition between the relevant complex manifolds.

The paper studies the zero-slope-parameter limit, governed by the IIB system, and obtains existence and nonexistence results for highly symmetric non-compact local models. These results do not settle solvability of the full Hull–Strominger Bianchi identity through general conifold transitions.