Title:
harmonic bundle and D-module

Abstract:
Recently, harmonic bundles with tame singularity have been studied,
and we obtained a nice applicatoin to the theory of D-modules.
It is attractive and challenging to obtain the generalization for
harmonic bundles with non-tame singularity.
It is expected to lead us deeper understanding of irregular singularities
of flat connections and D-modules on higher dimensional varieties.

After giving an overview of the study on tame harmonic bundles
and the application to D-modules,
we will explain what is known and what should be known
for non-tame harmonic bundles.