English
The total degree of p − q does not exceed the maximum of the total degrees of p and q.
Русский
Общая степень p − q не превосходит max(totalDegree p, totalDegree q).
LaTeX
$$$(a - b).totalDegree \\le \\max(a.totalDegree, b.totalDegree)$$$
Lean4
theorem totalDegree_sub (a b : MvPolynomial σ R) : (a - b).totalDegree ≤ max a.totalDegree b.totalDegree :=
calc
(a - b).totalDegree = (a + -b).totalDegree := by rw [sub_eq_add_neg]
_ ≤ max a.totalDegree (-b).totalDegree := (totalDegree_add a (-b))
_ = max a.totalDegree b.totalDegree := by rw [totalDegree_neg]