The following rings are integral domains<br>
1. The ring of integers<br>
2. The ring of Gaussian integers
(that is, <i>Z</i>[<i>i</i> ] = {<i>a + bi </i>| <i>a, b</i> in <i>Z</i>}) is an integral domain.<br>
4. The ring <i>Z</i>[<i>x</i>] of polynomials with integer coefficients. <br>
6. The ring <i>Z<sub>p</sub></i> of integers modulo <i>p</i>, <i>p</i> is prime.<br>