Currently, monadic ↑ acts as if it was called dyadically with 1 as its left argument, while monadic ↓ raises a VALENCE ERROR. In almost every single case where I have used ↓, it has been in the form 1↓X. Is there a reason why the monadic form is not allowed?
And if not, would it make sense to add as an extension? Since the current behaviour is to raise an error there should be no backwards-compatibility issues.
Regards,
Elias