English
Equality of LieSubalgebras is detected by equality of their ambient sets via coe.
Русский
Равенство подалгебр определяется равенством их анимационных множеств через приведение.
LaTeX
$$$$\forall {R} {L} [\text{CommRing } R] [\text{LieRing } L] [\text{LieAlgebra } R L]\ (L_1'\ L_2' : \text{LieSubalgebra } R L),\ ((L_1' : \text{Set } L) = (L_2' : \text{Set } L)) \iff L_1' = L_2'. $$$$
Lean4
@[norm_cast]
theorem coe_set_eq (L₁' L₂' : LieSubalgebra R L) : (L₁' : Set L) = L₂' ↔ L₁' = L₂' :=
SetLike.coe_set_eq