no goals
G : Type u_1
inst✝ : Group G
H K L : Subgroup G
⊢ relindex H (K ⊓ L) * relindex K L = relindex (H ⊓ K) L
rw [← inf_relindex_right H (K ⊓ L), ← inf_relindex_right K L, ← inf_relindex_right (H ⊓ K) L,
  inf_assoc, relindex_mul_relindex (H ⊓ (K ⊓ L)) (K ⊓ L) L inf_le_right inf_le_right]