revert hxs
α : Type u
inst✝¹ : LinearLT α
inst✝ : DecidableRel LT.lt
deg : α → Nat
xs : FreeCMonoid α
hxs : degree deg xs = 0
hdeg_pos : autoParam (∀ (a : α), deg a > 0) _auto✝
⊢ xs = 1
α : Type u
inst✝¹ : LinearLT α
inst✝ : DecidableRel LT.lt
deg : α → Nat
xs : FreeCMonoid α
hdeg_pos : autoParam (∀ (a : α), deg a > 0) _auto✝
⊢ degree deg xs = 0 → xs = 1