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