Xt=(X−1)−1X^{t}=\left(X^{-1}\right)^{-1}Xt=(X−1)−1
Y−X=X−YY-X=X-YY−X=X−Y
X+Y≠Y+XX+Y \neq Y+XX+Y=Y+X
(Yt)t=Y\left(Y^{t}\right)^{t}=\mathrm{Y}(Yt)t=Y