Abstract:
In tame geometry, a cell (or cylinder) is defined as follows. A one
dimensional cell is an interval; a two-dimensional cell is the domain
bounded between the graphs of two functions on a one-dimensional cell;
and so on. Cellular decomposition (covering or subdividing a set into
cells) and preparation theorems (decomposing the domain of a function
into cells where the function has a simple form) are two of the key
technical tools in semialgebraic, subanalytic and o-minimal geometry.
Cells are normally seen as intrinsically real objects, defined in
terms of the order relation on $\mathbb R$. We (joint with Novikov)
introduce the notion of complex cells, a complexification of
real cells where real intervals are replaced by complex
annuli. Complex cells are naturally endowed with a notion of analytic
extension to a neighborhood, called $\delta$-extension. It turns out
that complex cells carry a rich hyperbolic-geometric structure, and
the geometry of a complex cell embedded in its $\delta$-extension
offers powerful new tools from geometric function theory that are
inaccessible in the real setting. Using these tools we show that the
real cells of the subanalytic cellular decomposition and preparation
theorems can be analytically continued to complex cells.
Complex cells are closely related to uniformization and resolution of
singularities constructions in local complex analytic geometry. In
particular we will see that using complex cells, these constructions
can be carried out uniformly over families (which is impossible in the
classical setting). If time permits I will also discuss how this
relates to the Yomdin–Gromov theorem on $C^k$-smooth resolutions and
some modern variations.