making derivations from given rules

GIVEN
#####################################################
@prefix math: <http://www.w3.org/2000/10/swap/math#>.
@prefix log: <http://www.w3.org/2000/10/swap/log#>.
@prefix : <http://www.agfa.com/w3c/euler/testLF#>.

{?P :needs :Test; :testSeverity ?X. ?X math:lessThan 50} => {?P :needs 
:NormalTreatment}.
{?P :needs :Test; :testSeverity ?X. ?X math:notLessThan 50} => {?P :needs 
:SpecialTreatment}.

{?C => {?P :needs ?S}. ?C log:includes {?P :needs ?X}} => {?X :choose ?S}.
#####################################################


QUERY
#####################################################
@prefix : <http://www.agfa.com/w3c/euler/testLF#>.

{?U :choose ?V} => {?U :choose ?V}.
#####################################################


ANSWER
#####################################################
:Test :choose :NormalTreatment.
:Test :choose :SpecialTreatment.
#####################################################


and is what I get with euler5; in a more elaborate test case
cwm was also giving such derivation, but not in this case..
only when making GIVEN like

#####################################################
@prefix math: <http://www.w3.org/2000/10/swap/math#>.
@prefix log: <http://www.w3.org/2000/10/swap/log#>.
@prefix : <http://www.agfa.com/w3c/euler/testLF#>.

{?P :needs :Test; :testSeverity ?X. ?X math:lessThan 50} => {?P :needs 
:NormalTreatment}.
{?P :needs :Test; :testSeverity ?X. ?X math:notLessThan 50} => {?P :needs 
:SpecialTreatment}.

{?P :needs ?S} => {?P :requires ?S}.
{?C => {?P :needs ?S}. ?C log:includes {?P :needs ?X}} => {?X :choose ?S}.
#####################################################


cwm answered with

#####################################################
     @prefix : <http://www.agfa.com/w3c/euler/testLF#> .
 
    :Test     :choose :NormalTreatment,
                :SpecialTreatment .
#####################################################


Now I see that GIVEN

#####################################################
@prefix math: <http://www.w3.org/2000/10/swap/math#>.
@prefix log: <http://www.w3.org/2000/10/swap/log#>.
@prefix : <http://www.agfa.com/w3c/euler/testLF#>.

{?P :needs :Test; :testSeverity ?X. ?X math:lessThan 50} => {?P :needs 
:NormalTreatment}.
{?P :needs :Test; :testSeverity ?X. ?X math:notLessThan 50} => {?P :needs 
:SpecialTreatment}.

@forAll <#P>, <#S>, <#X>.
{?C => {<#P> :needs <#S>}. ?C log:includes {<#P> :needs <#X>}} => {<#X> 
:choose <#S>}.
#####################################################

is also working..


-- 
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/