VERY URGENT, CUT AND FINDALL/3

 Hi, 
    
  I have an urgent doubt. For example when I ask to prolog 
    
  ?- member( 3, [1,2,3]). 
  Yes 
    
  Is there any system variable associated with the prolog answer "Yes" or "No" ??? 
    
  I have this doubt because I want to use the answer in programs (e.g. if answer=Yes then ....) 
    

    
  
I know that is possible with :
The goal member(3,[1,2,3]) succeeds and you can use that in a 
conjunction or in an if-then-else, as in 

            member(3,[1,2,3]), writeln('3 is a member of [1,2,3]) 

or 

        (member(3,[1,2,3]) -> 
                writeln(success) 
        ; 
                writeln(failure) 
        ) 

but I need to Know how I can do with CUT.



And I want to know a program write a list who not belongs simultaniosly a two lists, and i want to use findall/3.
For example:
A=[1,2,3,4,5,6].
B=[3,4,8,7,6,1].
L=[2,5,8,7].

---

Sent from the SWI Prolog forum at Nabble.com:
VERY URGENT, CUT AND FINDALL/3