Submission date: 22 July 2019

Abstract:

We present several examples of hereditary classes of finite structures satisfying the joint embedding property and the weak amalgamation property, but failing the cofinal amalgamation property. These include a continuum-sized family of classes of finite undirected graphs, as well as an example due to Pouzet with countably categorical generic limit.

Mathematics Subject Classification: 03C07, 03C50

Keywords and phrases:

Full text arXiv 1907.09577: pdf, ps.