| P(H0), r0 ∈ (∅ ++ r)[r, o] ∪ H0, r0 ≠ r → (r0 ∈ H ↔ r0 ∈ H0), r0 = r ∨ r0 ∈ H → (H ++ r)[r0] = (r0 = r ⊃ o;H0[r0]) ⊦ r = null, P(H), r ∈ H, r ∈ H0, (r0 ∈ H0 ↔ r0 ∈ H) ∧ (r0 ∈ H0 → H0[r0] = H[r0]) |
(H ++ r)[r0] = (r0 = r ⊃ o;H0[r0]), P(H0), r0 ∈ (∅ ++ r)[r, o] ∪ H0, r0 ≠ r → (r0 ∈ H ↔ r0 ∈ H0) ⊦ r = null, P(H), r ∈ H0, r ∈ H, (r0 ∈ H0 ↔ r0 ∈ H) ∧ (r0 ∈ H0 → H0[r0] = H[r0])