Space of state vectors in -symmetric quantum mechanics

The space of states of -symmetric quantum mechanics is examined. The requirement that eigenstates with different eigenvalues must be orthogonal leads to the conclusion that eigenfunctions belong to a space with an indefinite metric. Self-consistent expressions for the probability amplitude and the average value of operator are suggested. Further specification of the space of state vectors yields a superselection rule, redefining the notion of the superposition principle. An expression for the probability current density, satisfying the equation of continuity and vanishing for the bound state, is proposed.