English

Jordan-Holder theorem for imprimitivity systems and maximal decompositions of rational functions

Complex Variables 2014-02-26 v2 Algebraic Geometry Group Theory

Abstract

In this paper we prove several results about the lattice of imprimitivity systems of a permutation group containing a cyclic subgroup with at most two orbits. As an application we generalize the first Ritt theorem about functional decompositions of polynomials, and some other related results. Besides, we discuss examples of rational functions, related to finite subgroups of the automorphism group of the sphere for which the first Ritt theorem fails to be true.

Keywords

Cite

@article{arxiv.0712.3869,
  title  = {Jordan-Holder theorem for imprimitivity systems and maximal decompositions of rational functions},
  author = {M. Muzychuk and F. Pakovich},
  journal= {arXiv preprint arXiv:0712.3869},
  year   = {2014}
}

Comments

In the current version the approach was considerably simplified and a lot of new material was added (see e.g. Section 2.2, Section 2.3 and Section 3.2). On the other hand, some results of rather calculating character were removed