Obviously also PCEBs with evolutionary time scales longer than the Hubble-time will form CVs, but they differ from the progenitors of present-day CVs. This difference is the only reason for our definition of "pre-CVs''.

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In this context we note that it might be easier to test our understanding of AML using a large (not yet identified) sample of PCEBs, as all the complications related to mass transfer are not present in these binaries.

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...

Note that the same method can not be applied in CVs, as accretion (re)heats the white dwarf. As a result, white dwarfs in CVs are typically hotter than field white dwarfs of comparable age and mass (Townsley & Bildsten 2002; Gänsicke 2000).

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... AML prescription

Notice, $\dot{J}_{{\rm RMB}}$ is smaller than $\dot{J}_{{\rm CMB}}$ only above the gap otherwise $\dot{J}_{{\rm RMB}}$ is more efficient.

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... $\tau_0=1.3\times10^{10}$ yrs

Recently Ferreras et al. (2001) set new constraints on the age of the universe combining the results obtained by cosmochromology, stellar population synthesis, and mapping of the peaks in the microwave background. They derived an age of 13.2^+1.2_-0.8 Gyrs. Note also that Cayrel et al. (2001) obtained a stellar age of $12.5\pm3$ Gyrs from uranium decay. Throughout this work we therefore assume that star formation in the Galaxy began 13 Gyrs ago.

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