  Although structural maps such as subductions and inductions appear naturally
in diffeology, one of the challenges is providing suitable analogous for
submersions, immersions, and \'{e}tale maps (i.e., local diffeomorphisms)
consistent with the classical versions of these maps between manifolds. In this
paper, we consider diffeological submersions, immersions, and \'{e}tale maps as
an adaptation of these maps to diffeology by a nonlinear approach. In the case
of manifolds, there is no difference between the classical and diffeological
versions of these maps. Moreover, we study their diffeological properties from
different aspects in a systematic fashion with respect to the germs of plots.
We also discuss notions of embeddings of diffeological spaces and regard
diffeological embeddings similar to those of manifolds. In particular, we show
that diffeological embeddings are inductions.
  In order to characterize the considered maps from their linear behaviors, we
introduce a class of diffeological spaces, so-called diffeological \'etale
manifolds, which not only contains the usual manifolds but also includes
irrational tori. We state and prove versions of the rank and implicit function
theorems, as well as the fundamental theorem on flows in this class. As an
application, we use the results of this work to facilitate the computations of
the internal tangent spaces and diffeological dimensions in a few interesting
cases.
