Editing Metric signature (section)

=== Matrices ===
The signature of the {{nowrap|''n''&thinsp;×&thinsp;''n''}} [[identity matrix]] is {{nowrap|(''n'', 0, 0)}}. The signature of a [[diagonal matrix]] is the number of positive, negative and zero numbers on its [[main diagonal]].

The following matrices have both the same signature {{nowrap|(1, 1, 0)}}, therefore they are congruent because of [[Sylvester's law of inertia]]:
:<math>\begin{pmatrix} 1 & 0  \\ 0 & -1 \end{pmatrix}, \quad \begin{pmatrix} 0 & 1  \\ 1 & 0 \end{pmatrix}. </math>