The IsLeftAlternative command returns true if the given magma satisfies the left alternative law X(XY) = (XX)Y.  It returns false otherwise.

$\mathrm{with}\left(\mathrm{Magma}\right)\:$

$m≔⟨⟨⟨1\|2\|3⟩\,⟨2\|3\|1⟩\,⟨3\|1\|2⟩⟩⟩$

$m≔\left[\begin{array}{ccc}1& 2& 3\\ 2& 3& 1\\ 3& 1& 2\end{array}\right]$

$\mathrm{IsLeftAlternative}\left(m\right)$

$\mathrm{true}$

$m≔⟨⟨⟨1\|2\|3⟩\,⟨2\|3\|3⟩\,⟨3\|1\|2⟩⟩⟩$

$m≔\left[\begin{array}{ccc}1& 2& 3\\ 2& 3& 3\\ 3& 1& 2\end{array}\right]$

$\mathrm{IsLeftAlternative}\left(m\right)$

$\mathrm{false}$

The Magma[IsLeftAlternative] command was introduced in Maple 15.

For more information on Maple 15 changes, see Updates in Maple 15.