Exclude individuals that is related by some specific inverse properties

I have some individuals A,B,C,D,E, and two properties P1, P2.

A P1 B
C P1 D
E P2 C

I want to build a Class that only captures A but not C. so I set a Class like,

1. myClass EquivalentTo: (P1 some owl:Thing) and (P1 only owl:Thing)
2. myClass EquivalentTo: (P1 some owl:Thing) and (not inverse P2 some owl:Thing)

but all of those tries failed. How can I differentiate the individual A and C?

myClass EquivalentTo: (P1 some owl:Thing) and (P1 only owl:Thing)

fails because the class expression is really equivalent to P1 some Thing. Since every individual is an instance of Thing, the right hand side of the intersection really doesn't add anything.

myClass EquivalentTo: (P1 some owl:Thing) and (not inverse P2 some owl:Thing)

This is actually correct for the description that you gave. You want individuals that have some value for P1 (good), and that are not the P2 value of some other individual. This is the way to describe that.

I think the issue that you're having is that while while your data set doesn't contain any triples of the form

    x P2 A

there's nothing in the ontology that says that such a thing is impossible. So you can't be sure that A actually has the type (not inverse P2 some Thing). This phenomenon is known as the open world assumption (OWA). If you search for that, you'll find some other questions on Stack Overflow about OWA in OWL. See, for instance:

• Why is this DL-Query not returning any individuals?
• Strange query behaviour in OWL!

In this case, if you want to say that A isn't the P2 value of some other individual, you'd probably have to do it manually, by adding a type to A like:

    inverse P2 only owl:Nothing

Once you do that, you'll get the results you want: