Extending partial isometries of antipodal graphs

Abstract

We prove EPPA (extension property for partial automorphisms) for all antipodal classes from Cherlin's list of metrically homogeneous graphs, thereby answering a question of Aranda et al. This paper should be seen as the first application of a new general method for proving EPPA which can bypass the lack of an automorphism-preserving completion. It is done by combining the recent strengthening of the Herwig--Lascar theorem by Hubi\v{c}ka, Ne\v{s}et\v{r}il and the author with the ideas of the proof of EPPA for two-graphs by Evans et al.