You know CL doesn't have a set type, though, right? It supports lists because it has to use a different data type. This turns several O(1) set functions into O(

You know CL doesn't have a set type, though, right? It supports lists because it has to use a different data type. This turns several O(1) set functions into O(n), however. Also, are you sure vectors are supported in CL? Looking over Common Lisp the Language, the adjoin/member/intersection functions only mention lists. Finally, it's not even clear CL won't return buggy values, either. From the documentation on CL's intersection function: "If either list has duplicate entries, the redundant entries may or may not appear in the result." So it's just as GIGO as Clojure.