## Hyperreal Number

Hyperreal numbers are an extension of the Real Numbers to include certain classes of infinite and infinitesimal numbers. A hyperreal number is said to be finite Iff for some Integer . is said to be infinitesimal Iff for all Integers .

References

Keisler, H. J. ``The Hyperreal Line.'' In Real Numbers, Generalizations of the Reals, and Theories of Continua (Ed. P. Ehrlich). Norwell, MA: Kluwer, 1994.