### Single Idea 17759

#### [catalogued under 4. Formal Logic / F. Set Theory ST / 6. Ordering in Sets]

Full Idea

Ordinals play the central role in set theory, providing the paradigmatic well-orderings.

Gist of Idea

Ordinals play the central role in set theory, providing the model of well-ordering

Source

Michal Walicki (Introduction to Mathematical Logic [2012], 2.3)

Book Reference

Walicki,Michal: 'Introduction to Mathematical Logic' [World Scientific 2012], p.89

A Reaction

When you draw the big V of the iterative hierarchy of sets (built from successive power sets), the ordinals are marked as a single line up the middle, one ordinal for each level.