English
For each p-adic number q, ratNorm(q) provides a rational value representing ‖q‖.
Русский
Для каждого p‑адического числа q функция ratNorm(q) задаёт рациональное значение, представляющее ‖q‖.
LaTeX
$$$\\|q\\| = \\operatorname{ratNorm}(q)\\,.$$$
Lean4
/-- `ratNorm q`, for a `p`-adic number `q` is the `p`-adic norm of `q`, as rational number.
The lemma `padicNormE.eq_ratNorm` asserts `‖q‖ = ratNorm q`. -/
def ratNorm (q : ℚ_[p]) : ℚ :=
Classical.choose (padicNormE.is_rat q)