in Fig. \[fig3\].

![The evolution of the He core mass ($M_{\rm cHe}$) and of the mass shell where the He-burning energy release is at maximum \[$M(\epsilon^{\rm He}_{\rm
max})$\] for different model sequences. The notation of the models follows Table \[tab1\], where the input physics of the various sequences is defined. The solid line corresponds to our standard model. The symbol $\dagger$ is used to identify the models experiencing the H-flash. \[fig3\]](fig3.eps){width="\columnwidth"}

Significantly different results were found by  @FIH90. In their model (of same mass) the size of the H-exhausted core at He-flash ignition is $0.528\,M_\odot$ and $M(\epsilon^{\rm He}_{\rm max})$ is $0.41\,M_\odot$. We do not know the reason for such a large difference in the location of the He-flash ignition, but we suspect it could be due to the choice of radiative and/or conductive opacities adopted by @FIH90, or differences in the treatment of plasma-neutrino emission. It should be emphasized that the value of $M(\epsilon^{\rm He}_{\rm
max})$ is very important for the occurrence of a H-flash. The closer $M(\epsilon^{\rm He}_{\rm max})$ is to the border of the He core, the higher is the probability for the HECZ to reach the H-rich layer.

Soon after the He-flash sets in a convective shell 