On the renormalization group iteration of a two-dimensional hierarchical non-linear -model
Scale-dependent functions, stochastic quantization and renormalization.
Status report on the instanton counting.
Two Hartree-Fock models for the vacuum polarization
We review recent results about the derivation and the analysis of two Hartree-Fock-type models for the polarization of vacuum. We pay particular attention to the variational construction of a self-consistent polarized vacuum, and to the physical agreement between our non-perturbative construction and the perturbative description provided by Quantum Electrodynamics.