Here is the definition of RecallNumber in the Aleph Manual. As I understand it so far RecallNumber defines an upper bound (Either a number or * for unbounded) for "the number of successfull calls" of a given predicate. But I'm lost on the context of the "successfull calls". Is this at some point during the search for a clause? Or does it bound the number of times the predicate can appear in the body of the learned clause? Something else?
I would appreciate any explanation or links to explanations.