Type I supernovae and accretion-induced collapses from cataclysmic variables?

The possibility that the white dwarfs in cataclysmic variables might grow in mass to the Chandrasekhar limit is examined. It is demonstrated that the masses of the white dwarfs in classical nova systems generally decrease as a result of nova explosions. Observational and theoretical evidence is presented in support of the view that the masses of the white dwarfs in recurrent nova systems increase. The critical parameters for which a mass increase is obtained are approximately greater than 1.2 solar mass for the white dwarf mass and greater than 10 exp -8 solar mass/yr for the accretion rate. The systems in which the white dwarfs are most likely to reach the Chandrasekhar limit are those which satisfy the above limits on the mass of the white dwarf and on the accretion rate and in which, in addition, the secondary stars are transfering helium-rich material. A subclass of the recurrent novae satisfies all of these conditions.