lemma lveq_inv_atom_atom: ∀n1,n2. ⋆ ≋ⓧ*[n1,n2] ⋆ → ∧∧ 0 = n1 & 0 = n2.
* [2: #n1 ] * [2,4: #n2 ] #H
[ elim (lveq_inv_succ … H)
lemma lveq_inv_atom_atom: ∀n1,n2. ⋆ ≋ⓧ*[n1,n2] ⋆ → ∧∧ 0 = n1 & 0 = n2.
* [2: #n1 ] * [2,4: #n2 ] #H
[ elim (lveq_inv_succ … H)