On Calabi--Yau fractional complete intersections

Abstract: In this article, we study mirror symmetry for pairs of singular Calabi--Yau manifolds which are double covers of toric manifolds. Their period integrals can be seen as certain `fractional' analogues of those of ordinary complete intersections. This new structure can then be used to solve their Riemann--Hilbert problems. The latter can then be used to answer definitively questions about mirror symmetry for this class of Calabi--Yau manifolds.