Yes, just ask for one. Consider list_length(A, -1) this is asking if any list A ...

		RichardLake on April 8, 2019 \| parent \| context \| favorite \| on: Simply Logical: Intelligent Reasoning by Example (... Yes, just ask for one. Consider `list_length(A, -1)` this is asking if any list A has a length of -1. If the guard is not there the second rule is valid, and a infinite recursion can result.