| r1 ∈ H, r1 ∈ H -- r0 ⊦ (H -- r0)[r1] = (H ++ r)[r1], r = null, r0 = r, r1 = r0, r1 = r, r ∈ H, r ∈ H -- r0 |
r1 ∈ H ⊦ H[r1] = (H ++ r)[r1], r = null, r0 = r, r1 = r0, r ∈ H
Used simplifier rules: at-del: r ∈ H ⊦ r ≠ r0 → (H -- r0)[r] = H[r];%in-del: ⊦ r ∈ H -- r0 ↔ r ≠ r0 ∧ r ∈ H;