English
A separable polynomial is squarefree.
Русский
Разделимый многочлен квадратно свободен.
LaTeX
$$$\\operatorname{Separable}(p) \\Rightarrow \\operatorname{Squarefree}(p)$$$
Lean4
/-- A separable polynomial is square-free.
See `PerfectField.separable_iff_squarefree` for the converse when the coefficients are a perfect
field. -/
theorem squarefree {p : R[X]} (hsep : Separable p) : Squarefree p := by
classical
rw [squarefree_iff_emultiplicity_le_one p]
exact fun f => or_iff_not_imp_right.mpr fun hunit => emultiplicity_le_one_of_separable hunit hsep