  The two kinds of indirect CP violation in neutral meson systems are related,
in the absence of new weak phases in decay. The result is a model-independent
expression relating CP violation in mixing, CP violation in the interference of
decays with and without mixing, and the meson mass and width differences. It
relates the semileptonic and time-dependent CP asymmetries; and CP-conjugate
pairs of time-dependent $D^0$ CP asymmetries. CP violation in the interference
of decays with and without mixing is related to the mixing parameters of
relevance to model building: the off-diagonal mixing matrix elements |M12|,
|Gamma12|, and phi12 = arg(M12 /Gamma12). Incorporating this relation into a
fit to the D0 -\overline{D0} mixing data implies a level of sensitivity to
|phiD12| of 0.10 [rad] at 1 sigma. The formalism is extended to include new
weak phases in decay, and in Gamma12. The phases are highly constrained by
direct CP violation measurements. Consequently, the bounds on |phiD12| are not
significantly altered, and the effects of new weak phases in decay could be
difficult to observe at a high luminosity flavor factory (D0) or at the LHC
(Bs) via violations of the above relations, unlike in direct CP violation.
