English
A nontrivial torsion abelian group is not torsion-free.
Русский
Непустая торовая абелевация не торовоподобна.
LaTeX
$$Not (IsMulTorsionFree(G)) given (IsTorsion G) and Nontrivial G$$
Lean4
/-- A nontrivial torsion abelian group is not torsion-free. -/
@[to_additive /-- A nontrivial additive torsion abelian group is not torsion-free. -/
]
theorem not_isMulTorsionFree_of_isTorsion [Nontrivial G] (hG : IsTorsion G) : ¬IsMulTorsionFree G :=
not_isMulTorsionFree_iff_isOfFinOrder.2 <|
let ⟨x, hx⟩ := exists_ne (1 : G);
⟨x, hx, hG x⟩