We define a map of simplicial presheaves, the Chern character, that assigns to
every sequence of composable non-connection- preserving isomorphisms of
vector bundles with holomorphic connections an appropriate sequence of
holomorphic forms. We apply this Chern character map to the Čech nerve
of a good cover of a complex manifold and assemble the data by passing
to the totalization to obtain a map of simplicial sets. In simplicial degree
, this map gives
a formula for the Chern character of a bundle in terms of the clutching functions. In simplicial
degree
,
this map gives a formula for the Chern character of bundle maps. In each simplicial degree
beyond
,
these invariants, defined in terms of the transition functions, govern the
compatibilities between the invariants assigned in previous simplicial degrees. In
addition to this, we apply this Chern character to complex Lie groupoids to obtain
invariants of bundles on them in terms of the simplicial data. For group actions, these
invariants land in suitable complexes calculating various Hodge equivariant
cohomologies. In contrast, the de Rham Chern character formula involves additional
terms and will appear in a sequel paper. In a sense, these constructions build on
a point of view of “characteristic classes in terms of transition functions”
advocated by Raoul Bott, which has been addressed over the years in various
forms and degrees, concerning the existence of formulas for the Hodge and de
Rham characteristic classes of bundles solely in terms of their clutching
functions.