This trait is for multi-dimensional tensors that can logically have one of their dimensions "collapsed", e.
Marker for being able to map the keys and values in a value collection to new values.
Marker for being able to transform the keys and values in a value collection to new values.
Basically Function1, but not because we don't want these coming up when implicit search happens.
A Multimethod is basically a glorified registry that uses dynamic reflection (and subtyping) to determine which version of the method to invoke.
A Multiproc2 is a Multimethod that is guaranteed to return Unit
"Universal" Functions that mimic numpy's.
A "Universal Reducer" Function that can support reduction-type operations on a collection or some such.
An object is UReduceable (Universally Reduceable) if it can deal with URFuncs in an intelligent manner.