English
The p-adic norm is non-archimedean: padicNorm p (q + r) ≤ max(padicNorm p q, padicNorm p r).
Русский
Nон-архи-метрическая норма: padicNorm p (q + r) ≤ max(padicNorm p q, padicNorm p r).
LaTeX
$$$ padicNorm\ p\ (q + r) \leq \max( padicNorm\ p\ q, padicNorm\ p\ r ) $$$
Lean4
/-- The `p`-adic norm is nonarchimedean: the norm of `p + q` is at most the max of the norm of `p`
and the norm of `q`. -/
protected theorem nonarchimedean {q r : ℚ} : padicNorm p (q + r) ≤ max (padicNorm p q) (padicNorm p r) :=
by
wlog hle : padicValRat p q ≤ padicValRat p r generalizing q r
· rw [add_comm, max_comm]
exact this (le_of_not_ge hle)
exact nonarchimedean_aux hle