Hanf Numbers and Presentation Theorems in AECs

Will Boney, John Baldwin

Published 2015-11-09Version 1

We prove that a strongly compact cardinal is an upper bound for a Hanf number for amalgamation, etc. in AECs using both semantic and syntactic methods. To syntactically prove non-disjoint amalgamation, a different presentation theorem than Shelah's is needed. This relational presentation theorem has the added advantage of being {\it functorial}, which allows the transfer of amalgamation.