English
For any x ∈ hat K, there exists r ∈ K with extensionValuation(x) = v(r).
Русский
Для любого x ∈ hat K существует r ∈ K с extensionValuation(x) = v(r).
LaTeX
$$$\exists r \in K\; extensionValuation(x) = v(r)$$$
Lean4
theorem exists_coe_eq_v (x : hat K) : ∃ r : K, extensionValuation x = v r :=
by
rcases eq_or_ne x 0 with (rfl | h)
· use 0
exact extensionValuation_apply_coe 0
· refine Completion.denseRange_coe.induction_on x ?_ (by simp)
simpa [eq_comm] using valuation_isClosedMap.isClosed_range.preimage continuous_extensionValuation