English
If p is prime, then primeFactorsList p = [p].
Русский
Если p простое, то primeFactorsList p = [p].
LaTeX
$$$ \forall p,\ \text{Nat.Prime}(p) \Rightarrow \text{primeFactorsList}(p) = [p] $$$
Lean4
theorem primeFactorsList_prime {p : ℕ} (hp : Nat.Prime p) : p.primeFactorsList = [p] :=
by
have : p = p - 2 + 2 := Nat.eq_add_of_sub_eq hp.two_le rfl
rw [this, primeFactorsList]
simp only [Eq.symm this]
have : Nat.minFac p = p := (Nat.prime_def_minFac.mp hp).2
simp only [this, primeFactorsList, Nat.div_self (Nat.Prime.pos hp)]