  We study differential equations for Feynman amplitudes and we show that the
corresponding D-module is isomorphic to a GKZ D-modules. We show that the sheaf
of solutions to the D-module is isomorphic to a certain relative homology and
the amplitudes are periods of a relative motive. Using these ideas, we develop
a method of regularization which specializes to dimensional regularization and
analytic regularization.
