Squashed entanglement, also called CMI entanglement (CMI can be pronounced "see me"), is an information theoretic measure of quantum entanglement for a bipartite quantum system. If formula_1 is the density matrix of a system formula_2 composed of two subsystems formula_3 and formula_4, then the CMI entanglement formula_5 of system formula_2 is defined by
Squashed entanglement is not known as CMI entanglement.