Definition 1. Every well-ordered set $W$ is isomorphic to a unique ordinal number. This unique ordinal number is called the order type of $W$ (with respect to the given well-order).
References
- [1]
- Wikipedia contributors. Order type. Wikipedia, The Free Encyclopedia.
- [2]
- Thomas Jech. Set Theory. 3rd Millennium ed, rev. and expanded. Springer, 2002. p. 20.