English
The exponential characteristic is one iff the characteristic is zero.
Русский
Экспоненциальная характеристика равна единице тогда и только тогда, когда характеристика равна нулю.
LaTeX
$$$\\\\forall R (p,q) [CharP R p] [ExpChar R q], q = 1 \\\\Leftrightarrow p = 0$$$
Lean4
/-- The exponential characteristic is one iff the characteristic is zero. -/
theorem expChar_one_iff_char_zero (p q : ℕ) [CharP R p] [ExpChar R q] : q = 1 ↔ p = 0 :=
by
constructor
· rintro rfl
exact char_zero_of_expChar_one R p
· rintro rfl
exact expChar_one_of_char_zero R q