Residue currents on singular varieties
Doctoral thesis, 2012
This thesis concerns various aspects of the theory of residue currents. Particularly, we study residue currents on singular varieties and duality theorems
for such currents.
On a singular variety, there are various notions of holomorphic functions.
In Paper I, we study how to extend the definition of Coleff-Herrera products
and Bochner-Martinelli type residue currents from the case of strongly holomorphic functions to weakly holomorphic functions, and investigate how various properties known in the strongly holomorphic case transform into the
weakly holomorphic case.
The duality theorem for Coleff-Herrera products on a complex manifold is
one of the key properties of the Coleff-Herrera product. On a singular variety,
the duality theorem for Coleff-Herrera products is in general false. In Paper II,
we discuss necessary and sufficient conditions for when the duality theorem
holds, and in particular we show that on any singular variety, one can find
examples where the duality principle fails.
Another important property of the Coleff-Herrera product is the transformation law. In Paper III, we describe a comparison formula for Andersson-Wulcan currents, generalizing the transformation law. Applications of this formula include giving a proof by means of residue currents of a theorem of Hickel
related to the Jacobian of a holomorphic mapping, and constructing a current
on a singular variety satisfying the duality principle.
The failure of the duality theorem for Coleff-Herrera products leads to the
search for an alternative. In Paper IV, we elaborate on the construction in Paper III, of a current satisfying the duality principle for an arbitrary ideal. In
particular, using the comparison formula, we explain how we can view this
construction as an intrinsic construction on the variety, generalizing the construction of Andersson and Wulcan.
local analytic geometry
weakly holomorphic functions