Check if \((M,e,\star)\) is a commutative monoid then \((\mathbf{Disc}_M, =, e, \star)\) is a symmetric monoidal preorder, as described in this example.
Monotonicity is the only tricky one, and is addressed due to the triviality of the discrete preorder.
We can replace \(x \leq y\) with \(x \leq x\) because it is a discrete preorder.
\(x_1 \leq x_1 \land x_2 \leq x_2 \implies x_1 \otimes x_2 \leq x_1 \otimes x_2\)
\(True \land True \implies True\) is vacuously true due to reflexivity of preorder.
Unitality/associativity comes from unitality/associativity of monoid
Symmetry comes from commutitivity of monoid.