Surjectively rigid chains
We study rigidity properties of linearly ordered sets (chains) under automorphisms, order-embeddings, epimorphisms, and endomorphisms. We focus on two main cases, dense subchains of the real numbers, and uncountable dense chains of higher (regular) cardinalities. We also give a Fraenkel-Mostowski model which illustrates the role of the axiom of choice in one of the key proofs.
math.LO↗