  A hierarchical, reversible mapping between levels of tree structured
computation, applicable for structuring the Quantum Computation algorithm for
NP-complete problem is presented. It is proven that confining the state of a
quantum computer to a subspace of the available Hilbert space, where states are
consistent with the problem constraints, can be done in polynomial time. The
proposed mapping, together with the method of state reduction can be
potentially used for solving NP-complete problems in polynomial time.
