Problem with a list in CAS-program

[Arno K]

Quite clear, that collides with one possibility of defining a function in CAS, even after the CAS could see that l1 is a list, perhaps one can work at that point, but maybe ist difficult for the programmer to get that done, cas could get strict-types at declaration time which is unconvenient for the user, so the other possibilty is to check the construction for this recursive definition and if this error occurs CAS can simply use the assignment, which can be wrong, too.
But this will be Bernards task, I think.
Arno