no goals
α : Type u_1
inst✝² : CanonicallyOrderedAddMonoid α
inst✝¹ : Sub α
inst✝ : OrderedSub α
a b c d : α
ha : AddLECancellable a
hb : AddLECancellable b
hc : AddLECancellable c
hba : b ≤ a
hca : c ≤ a
⊢ a - b = a - c ↔ b = c
simp_rw [le_antisymm_iff, ha.tsub_le_tsub_iff_left hb hba, ha.tsub_le_tsub_iff_left hc hca,
  and_comm]