  FJRW theory is a formulation of physical Landau-Ginzburg models with a rich
algebraic structure, rooted in enumerative geometry. As a consequence of a
major physical conjecture, called the Landau-Ginzburg/Calabi-Yau
correspondence, several birational morphisms of Calabi-Yau orbifolds should
correspond to isomorphisms in FJRW theory. In this paper it is shown that not
only does this claim prove to be the case, but is a special case of a wider
FJRW isomorphism theorem, which in turn allows for a proof of mirror symmetry
for a new class of cases in the Landau-Ginzburg setting. We also obtain several
interesting geometric applications regarding the Chen-Ruan cohomology of
certain Calabi-Yau orbifolds.
