| ⊦ ((H -- r0) ++ r)[r, o] = (H ++ r)[r, o] -- r0, r = null, r0 = r, r ∈ H |
⊦ H0 = H1 ↔ (∀ r. (r ∈ H0 ↔ r ∈ H1) ∧ (r ∈ H0 → H0[r] = H1[r]))
⊦ r = null, r0 = r, r ∈ H, ∀ r1. (r1 ∈ ((H -- r0) ++ r)[r, o] ↔ r1 ∈ (H ++ r)[r, o] -- r0) ∧ (r1 ∈ ((H -- r0) ++ r)[r, o] → ((H -- r0) ++ r)[r, o][r1] = ((H ++ r)[r, o] -- r0)[r1])
Used terms: (H ++ r)[r, o] -- r0, ((H -- r0) ++ r)[r, o]