2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/88739This paper is withdrawn by the author. It is superseded by Makhlin's paper quant-ph/0002045.This paper is withdrawn by the author. It is superseded by Makhlin's paper quant-ph/0002045Quantum PhysicsThe space of local equivalence classes of mixed two-qubit statestext