[12] Show that if is a fixed one-to-one and onto computable function : {0, 1} {0, 1}, then for every x

[12] Show that if φ is a fixed one-to-one and onto computable function φ : {0, 1}∗ → {0, 1}∗, then for every x ∈ {0, 1}∗, C(x) − C(x|φ(x)) = C(x) + O(1) = C(φ(x)) + O(1).