| m < i, n < i, n0 < i, m < # A, n < # A, n0 < # A, i ≤ # A ⊦ n = n0, n = m, n0 = m, A[m] ∈ mkbag(A, i) -- A[n] -- A[n0] |
⊦ a ∈ bag ↔ count(a, bag) ≠ 0
count(A[m], mkbag(A, i) -- A[n] -- A[n0]) = 0, n0 < # A, n < # A, m < # A, n0 < i, n < i, m < i, i ≤ # A ⊦ n = m, n = n0, n0 = m
Used terms: mkbag(A, i) -- A[n] -- A[n0], A[m]