Commutative version of the local Hamiltonian problem and common eigenspace problem.

Sergey Bravyi Mikhail Vyalyi Commutative version of the local Hamiltonian problem and common eigenspace problem. 187-215 2005 5 Quantum Information & Computation 3 http://portal.acm.org/citation.cfm?id=2011639 db/journals/qic/qic5.html#BravyiV05