Free products of circularly ordered groups with amalgamated subgroup

Adam Clay, Tyrone Ghaswala

Published 2018-07-21Version 1

This paper gives necessary and sufficient conditions that the free product with amalgamation of circularly ordered groups admit a circular ordering extending the given orderings of the factors. Our result follows from establishing a categorical framework that allows the problem to be restated in terms of amalgamating certain left-ordered central extensions, where we are able to apply work of Bludov and Glass.