Application *to* superpositions is undefined

[pdarragh]

Currently, there is no special handling for what to do when a superposition is given as the argument of an application.

Because the only way to "observe" the internal terms of a superposition is to apply that specific superposition, superpositions-as-arguments can only reasonably be used in internal application forms. This is very limiting.

Perhaps a change to make would be forking interpretation whenever a superposition is used as an argument, then merging the forks into a new superposition.