Two Groups are isomorphic if the correspondence between them is One-to-One and the ``multiplication'' table is preserved. For example, the Point Groups and are isomorphic Groups, written or (Shanks 1993). Note that the symbol is also used to denote geometric Congruence.

**References**

Shanks, D. *Solved and Unsolved Problems in Number Theory, 4th ed.* New York: Chelsea, 1993.

© 1996-9

1999-05-26