2019/07/22 by Krawczyk, Adam, Kruckman, Alex, Kubiś, Wiesław +1
#03C07 #03C50 #FOS: Mathematics #Logic (math.LO)
paper · doi:10.48550/arxiv.1907.09577
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.