Definition 2.3.2.  Let M be a magma. We define
(M)
by:
([M, ∗]) := M  (M is a set, ∗ : M × M → M is an operation on M)
We write “let a ∈ M” for “let a ∈ (M).”
Remarks.

This definition retrieves a representative carrier set from a magma (which is actually an equivalence class of magmas), and enables typical abuse of notation.