∃ x. n = # x ∧ ls(r, x)(H) ⊦ r = null, ∃ x. ls(r, x)(H) ∧ n = # x
∃ x. ls(r, x)(H) ∧ n = # x ⊦ r = null, ∃ x. n = # x ∧ ls(r, x)(H)