| r ∈ rs, r ∈ H ⊦ H[r, o] \ rs = H \ rs |
r ∈ rs, r ∈ H ⊦ # rs = 0, H[r, o] \ rs = H \ rs, rs = ∅
Used simplifier rules: size-zero-01: ⊦ rs ≠ ∅ → # rs ≠ 0; (forward) from specification set-basic[refset]%ne-01: ⊦ r ∈ rs → rs ≠ ∅; (forward) from specification set-basic[refset]