Atomic model (mathematical logic)
Appearance
In model theory, an atomic model is a model which is in some sense small.
Properties
The back and forth method can be used to show that any two countable atomic models of a theory that are elementarily equivalent are isomorphic.
References
Chang, Chen Chung; Keisler, H. Jerome (1990) [1973], Model Theory, Studies in Logic and the Foundations of Mathematics (3rd ed.), Elsevier, ISBN 978-0-444-88054-3