| tree[parent(p0)].dir?, count(fid, tree.fids ∪ tree1.fids) < count(fid, tree[p0].fids), p0 ∈ tree, ∀ fid. count(fid, tree[p0].fids) ≤ count(fid, tree.fids) ⊦ p0 = ε, sdt0.fids ∪ ((tree.fids ∪ tree1.fids) \ tree[p0].fids) = ((sdt0.fids ∪ tree.fids) ∪ tree1.fids) \ tree[p0].fids, str ∈ sdt0 |
⊦ count(fid, fidb ∪ fidb0) = count(fid, fidb) + count(fid, fidb0)
tree[parent(p0)].dir?, count(fid, tree.fids) + count(fid, tree1.fids) < count(fid, tree[p0].fids), p0 ∈ tree, ∀ fid. count(fid, tree[p0].fids) ≤ count(fid, tree.fids) ⊦ p0 = ε, sdt0.fids ∪ ((tree.fids ∪ tree1.fids) \ tree[p0].fids) = ((sdt0.fids ∪ tree.fids) ∪ tree1.fids) \ tree[p0].fids, str ∈ sdt0
Used terms: tree1.fids, tree.fids, fid