@prefix math: <http://www.w3.org/2000/10/swap/math#>.
@prefix : <http://josd.github.io/brain#>.

{(?X) :fib ?Y} <= {(?X 1 1) :fib ?Y}.

{(0 ?A ?B) :fib ?B} <= {}.
{(1 ?A ?B) :fib ?B} <= {}.
{(?X ?A ?B) :fib ?Y} <= {?X math:greaterThan 1. ((?X 1)!math:difference ?B (?A ?B)!math:sum) :fib ?Y}.
