Résumé
We introduce the notion of Gamma-Lie bialgebras, where Gamma is a group. These objects give rise to cocommutative co-Poisson bialgebras, for which we construct quantization functors. This enlarges the class of co-Poisson algebras for which a quantization is known. Our result relies on our earlier work, where we showed that twists of Lie bialgebras can be quantized; we complement this work by studying the behavior of this quantization under compositions of twists. (c) 2008 Elsevier Inc. All rights reserved.