Ponderable 3.1.1

(a) $f=\left(\begin{array}{ccc}1& 2& 3\\ 3& 1& 2\end{array}\right)$.

(b) Clic on the image to open the odg file.

1<2 and f(1)=3>f(2)=1: first swap.

1<3 and f(1)=3>f(3)=2: second swap.

2<3 and f(2)=1>f(3)=2: no swap.

There are two swaps and its sign is (−1)²=1.

Maison