| elems nx1 ⊆ elems nx0, n0 = n ∨ n0 ∈ elems nx0 ∧ ¬ n0 ∈ elems nx1 ⊦ n ∈ nx0, (n0 = n ∨ n0 ∈ nx0) ∧ ¬ n0 ∈ nx1 |
elems nx1 ⊆ elems nx0, n0 = n ∨ n0 ∈ nx0 ∧ ¬ n0 ∈ nx1 ⊦ n ∈ nx0, (n0 = n ∨ n0 ∈ nx0) ∧ ¬ n0 ∈ nx1
Used simplifier rules: elems-def: ⊦ n ∈ elems nx ↔ n ∈ nx;