… We describe the category of regular holonomic modules over the ring D[[h]] of linear
differential operators with a formal parameter h. In particular, we establish the Riemann–
Hilbert correspondence and discuss the additional t-structure related to h-torsion. … Then
we establish our main result, the Riemann–Hilbert correspondence for regular holonomic
DX[[]]-modules, an -variant of Kashiwara’s classical theorem. In other words, we show that
the solution functor with values in OX[[]] induces an equivalence between the derived …