Minimal and Order-Minimal Structures

Before we get into details regarding number structures, we will examine definability in cases that are easier to analyze. We will define and give examples of minimal and order-minimal structures. The central concepts of type and symmetry, which were introduced in Chap. 2 , will be redefined in general model-theoretic terms and will be used to analyze the orderings of the sets of natural numbers, integers, and rationals.