| n < # ar, m ≤ # ar ⊦ ar.mapIf(φ, f, m)[n] = (n < m ∧ φ(ar[n]) ⊃ f(ar[n]);ar[n]) |
⊦ ar.mapIf(φ, f, n) = ar.mapIndices(ar.indicesWhere(φ, n), f)
n < # ar, m ≤ # ar ⊦ ar.mapIndices(ar.indicesWhere(φ, m), f)[n] = (n < m ∧ φ(ar[n]) ⊃ f(ar[n]);ar[n])
Used terms: m, f, φ, ar