Definition:Biquadratic Residue

Definition
Let $p$ be an odd prime.

Let $a \in \Z$ be an integer such that $a \not \equiv 0 \pmod p$.

Then $a$ is a biquadratic residue of $p$ $x^4 \equiv a \pmod p$ has a solution.

That is, :
 * $\exists x \in \Z: x^4 \equiv a \pmod p$

Also known as
A biquadratic residue is also known as a quartic residue.

Also see

 * Definition:Quadratic Residue