His work on ordered sets and ordinal numbers is fundamental to the subject. |
He worked on mathematical logic, in particular ordinal numbers, recursive arithmetic, analysis, and the philosophy of mathematics. |
Furthermore, ordinal numbers are less frequently encountered than are cardinal numbers. |
This pattern of language differences for ordinal numbers is reminiscent of findings for cardinal numbers in a number of ways. |
In 1905 Bernstein published an important article on transfinite ordinal numbers. |
However, it was not to be, but the second paper describes his theory of well-ordered sets and ordinal numbers. |