Approved BLD test ground equational call to factorial function Factorial function using equality in the head to have function return value. This test case also demonstrates recursion and the use of mathematical built-in predicates and functions corresponding to >, -, and *. Factorial_Functional-premise.rif http://www.w3.org/2005/rules/test/repository/tc/Factorial_Functional/Factorial_Functional-premise.rif ) Prefix(func ) Prefix(ex ) Group ( ex:factorial(0) = 1 Forall ?N ( ex:factorial(?N) = External(func:numeric-multiply( ?N ex:factorial(External(func:numeric-subtract(?N 1))))) :- External(pred:numeric-greater-than(?N 0)) ) ) ) ]]> Factorial_Functional-conclusion.rif http://www.w3.org/2005/rules/test/repository/tc/Factorial_Functional/Factorial_Functional-conclusion.rif