English
If R is a nonunital nonassociative ring, the integer action forms a scalar tower with R on itself.
Русский
Если R — некольцевое кольцо без единицы, целые образуют скалярную башню с R на себе.
LaTeX
$$IsScalarTower Int R R$$
Lean4
/-- Note that `AddCommGroup.int_isScalarTower` requires stronger assumptions on `R`. -/
instance int_isScalarTower [NonUnitalNonAssocRing R] : IsScalarTower ℤ R R where
smul_assoc n x
y :=
match n with
| (n : ℕ) => by simp_rw [natCast_zsmul, smul_assoc]
| -[n+1] => by simp_rw [negSucc_zsmul, smul_eq_mul, neg_mul, smul_mul_assoc]