A construction of maximal modular subspaces in local deformation theory (Q810210)

The authors study the question of universality of semi-universal deformations in a rather general setting. Their aim is to prove, under suitable assumptions, the existence of the maximal subspace R in the base space such that the restriction to this subspace is universal. This was carried out in the framework of operators of group germs on finite or infinite dimensional spaces. The authors use PO-spaces and PO-Lie groups as developed by J. Bingener and S. Kosarew [\textit{J. Bingener}, Lokale Modulräume in der analytischen Geometrie. Band 1 und 2. (1987; Zbl 0644.32001)]. Several characterizations of the modular subspace R are also given.