He sort of does. He seems to be able to read the simpler predicates that have been posted. Where he completely falls down is any form of synthesis of information.
In this whole interval successor discussion, he's finally accepted that intervals can have an order relation imposed on them. The only way he did that, though, was to translate it to the common order relation for numbers. The rest of us understand interval ordering to be based on numeric ordering; Doron has converted into numeric ordering.
That leaves him lost when faced with the concept of immediate successor; he hasn't synthesized the idea of interval ordering having its own existence, so he can't cope with immediate successors of intervals.
So, even when faced with a Mathematically precise definition for successor and for immediate successor, he cannot bridge from one to the other, even though he may understand the two separately.
You may have noticed, too, he's copy/pasted much of my Latex ad nauseum, but he is yet to post anything original. (Well, anything more intelligible than underscores with dots on them with no explanation of meaning.) I do not believe he can. Until I see evidence to the contrary, I will remain convinced Doron cannot express a complete thought with any rigor, either as a first-order predicate or even in reasonably plain English.