Let 

 be any of the following properties: the weak
        ideal property, the topological dimension zero,
        the combination of pure infiniteness and the
        ideal property, residual (SP), pure
        infiniteness, strong pure infiniteness, provided that the zero C*-algebra
        is included, and
        

-stability for a separable unital strongly self-absorbing
        C*-algebra 

.
        Let 

 be a separable unital C*-algebra with unit 

,
        and assume that there exist non-zero projections
        

, 

, in 

 such that 

.
        We show that 

 has 
 
 
 
 
        

 has 

        for every 
 
 
 
 
        
 has 

        (in fact, we prove a much more general
        result). We also show that, somehow surprisingly, for two large classes
        

 of non-zero C*-algebras, if 

,
        then the fact that 

 has the weak ideal property
        implies (or, is equivalent to) the fact that
        

 and 

 have the weak ideal property. We prove
        that one of these two results still holds if we replace the
        weak ideal property by some related properties.