Some fuzzy with cardinality restriction vs complex property in OWL

The OWL S&AS says:

To preserve decidability of reasoning in OWL Lite, not all properties can have cardinality restrictions placed on them or be specified as functional or inverse-functional. An individual-valued property is complex if 
1/ it is specified as being functional or inverse-functional, 
2/ there is some cardinality restriction that uses it, 
3/ it has an inverse that is complex, or 
4/ it has a super-property that is complex. 
Complex properties cannot be specified as being transitive. 


It seems OK, but some mistiness arises when diving into the deeps.

We know that:

someValuesFrom(owl:Thing) is logically equivalent to minCardinality(1)

and someValuesFrom(SomeNonEmptyClass) logically implies minCardinality(1)

My questions:

1. Suppose there is an existential restriction that uses a property, should the property be considered as a complex property?

It seems not. But how to explain the implication of the above axioms? 


2. Is there any meaning with minCardinality(0)? does it make the corresponding property become a complex property?

e.g.

restriction( myProperty minCardinality(0)) makes myProperty become a complex property?


Thanks for your concern!


Yuzhong Qu