A permutation of the n objects of a set E is all ordered combinations of these n elements. Therefore, a permutation of n objects in a set E of n elements is an n-tuple formed by these elements. If E [latex]= \left\{0, 1, 2, 3\right\}[/latex], then a permutation of E could be represented by the quadruplet [latex]\left(1, 0, 3, 2\right)[/latex], or the matrix: [latex]\begin{pmatrix} 0 & 1 & 2 & 3\\1 & 0 & 3 & 2\end{pmatrix}[/latex]. We can also describe a permutation as the set of ordered pairs that form the relation. In the previous case, we would have: {(0, 1), (1, 0), (2, 3), (3, 2)}. A permutation of a set of n elements is an arrangement of these n objects taken n at a time.