| count(A[n], mkbag(A, i0) ++ A[i0]) = 0, n < # A, i0 < # A, n ≤ i0, ∀ A0, n0. count(A0[n0], mkbag(A0, i0)) ≠ 0 ∨ ¬ n0 < i0 ∨ ¬ n0 < # A0 ∨ ¬ i0 ≤ # A0 ⊦ |
⊦ count(a, bag ++ b) = (a = b ⊃ 1;0) + count(a, bag)
(A[n] = A[i0] ⊃ 1;0) + count(A[n], mkbag(A, i0)) = 0, i0 < # A, n < # A, n ≤ i0, ∀ A0, n0. count(A0[n0], mkbag(A0, i0)) ≠ 0 ∨ ¬ n0 < i0 ∨ ¬ n0 < # A0 ∨ ¬ i0 ≤ # A0 ⊦
Used terms: A[i0], mkbag(A, i0), A[n]