English
For r ≥ 0 and x ∈ E, the div-inequality holds: ||x||/r ≤ egauge 𝕜 (ball 0 r) x.
Русский
Для r≥0 и x верно: ||x||/r ≤ egauge 𝕜 (ball 0 r) x.
LaTeX
$$$\\forall r\\in \\mathbb{R}_{\\ge 0},\\; \\frac{\\|x\\|}{r} \\le \\operatorname{egauge}_{\\mathbb{k}}(\\,\\mathsf{ball}\\, 0\, r, x).$$$
Lean4
theorem div_le_egauge_ball (r : ℝ≥0) (x : E) : ‖x‖ₑ / r ≤ egauge 𝕜 (ball 0 r) x :=
(div_le_egauge_closedBall 𝕜 r x).trans <| egauge_anti _ ball_subset_closedBall _