primes sieve from s s 0 from X cons X from s X head cons X Y X tail cons X Y Y if true X Y X if false X Y Y filter s s X cons Y Z if divides s s X Y filter s s X Z cons Y filter X sieve Y sieve cons X Y cons X filter X sieve Y primes 0 sieve 1 from 1 s 1 0 0 cons 2 head 1 tail 1 if 3 true 0 false 0 filter 2 divides 2 FULL ./TRS/nontermin/CSR/ExIntrod_GM99.trs