| n ≤ # ax ⊦ firstn(n, keys(fs, ax)) = keys(fs, firstn(n, ax)) |
# ax0 = n, ax = ax0 + ax1, n ≤ # ax ⊦ firstn(n, keys(fs, ax)) = keys(fs, ax0)
Used simplifier rules: ⊦ n ≤ # ax → ( ax0 = firstn(n, ax) ∧ ax1 = restn(n, ax) ↔ ax = ax0 + ax1 ∧ # ax0 = n); (elim) Used terms: ax, n, ax0, ax1