(1−1)(1−1)=(0−0)\left(\begin{array}{c}1 \\-1\end{array}\right)\left(\begin{array}{ll}1 & -1\end{array}\right)=(0-0)(1−1)(1−1)=(0−0)
(1−1)(1−1)=(00)\left(\begin{array}{c}1 \\-1\end{array}\right)\left(\begin{array}{ll}1 & -1\end{array}\right)=\left(\begin{array}{l}0 \\0\end{array}\right)(1−1)(1−1)=(00)
(1−1)(1−1)=(1−1−11)\left(\begin{array}{c}1 \\-1\end{array}\right)\left(\begin{array}{ll}1 & -1\end{array}\right)=\left(\begin{array}{cc}1 & -1 \\-1 & 1\end{array}\right)(1−1)(1−1)=(1−1−11)
(1−1)(1−1)=(2)\left(\begin{array}{c}1 \\-1\end{array}\right)\left(\begin{array}{ll}1 & -1\end{array}\right)=(2)(1−1)(1−1)=(2)
