English
If n ≠ 0 then conductor (1 : DirichletCharacter R n) = 1.
Русский
Если n ≠ 0, то conductor(1 : DirichletCharacter R n) = 1.
LaTeX
$$$n \neq 0 \Rightarrow \operatorname{conductor}(1 : \mathrm{DirichletCharacter}(R,n)) = 1$$$
Lean4
/-- The conductor of the trivial character is 1. -/
theorem conductor_one (hn : n ≠ 0) : conductor (1 : DirichletCharacter R n) = 1 :=
by
suffices FactorsThrough (1 : DirichletCharacter R n) 1
by
have h : conductor (1 : DirichletCharacter R n) ≤ 1 := Nat.sInf_le <| (mem_conductorSet_iff _).mpr this
exact Nat.le_antisymm h (Nat.pos_of_ne_zero <| conductor_ne_zero _ hn)
exact (factorsThrough_one_iff _).mpr rfl