A characterization of retracts in certain Frass limits
Assuming certain conditions on a class of finitely generated first-order structures admitting the model-theoretical construction of a Frass limit, we characterize retracts of such limits as algebraically closed structures in a class naturally related to . In this way we generalize an earlier description of retracts of the countably infinite random graph.
retract frass limit endomorphism algebraically closed structure. msc (2010) 03c15 03c50 08a35