Machine Learning, Mathematics, Linear Algebra, Physics.
which computes the distance between two points in the space. The function outputs a real number d(x, y) to every pair x, y ∈ X. The function should satisfy the following properties d(x, y) ≥ 0, for all pairs (x, y) ∈ X d(x, y) = 0, if x = y d(x, y) = d(y, x), for all pairs (x, y) ∈ X [Commutative