English
The center of a division ring is a field.
Русский
Центр деление кольца является полем.
LaTeX
$$center K is a Field$$
Lean4
instance instField : Field (center K)
where
inv a := ⟨a⁻¹, Set.inv_mem_center a.prop⟩
mul_inv_cancel _ ha := Subtype.ext <| mul_inv_cancel₀ <| Subtype.coe_injective.ne ha
div a b := ⟨a / b, Set.div_mem_center a.prop b.prop⟩
div_eq_mul_inv _ _ := Subtype.ext <| div_eq_mul_inv _ _
inv_zero := Subtype.ext inv_zero
nnqsmul := _
nnqsmul_def := fun _ _ => rfl
qsmul := _
qsmul_def := fun _ _ => rfl