No it shouldn't this is because for an empty list minimum is never evaluated as delete will handle the case of an empty list without touching it's first argument.

Ok I found my error, it was in my definitions for some and many. Perhaps it would be useful to have an explicit test for them in the test suite given to the user?

I've got everything working with the initial round of test cases. However when I try to submit I'm failing the tests entitled "pmap on number strings" I'm really not sure what I'm doing wrong here, some pointers would be much appreciated.