  This paper presents an analysis of decoherence resulting from the physically
real non-unitarity, or 'objective reduction,' that occurs in the Transactional
Interpretation (TI). Two distinct aspects of the decoherence process are
identified and disambiguated; specifically, (i) the resolution of the basic
measurement interaction with respect to the observable under study, and (ii)
the effect on the measured system of repetition of the measurement interaction.
It is shown that the measurement interaction as described in TI leads naturally
to the same quantitative expression for the decoherence function as in the
standard unitary-only account. However, unlike in the unitary-only approach,
under TI, the reduced density operator for the measured system can legitimately
be interpreted as representing the occurrence of an actual measurement result.
