omment cmt"><p>A Process maps indices to elements over values.</p><p>Elements, of course, have a universe. Wherever possible, operations on processes, such as getting elements, or mapping or chaining through
a function, produce an element in the same universe as the original element.
An exception is an element over an optional value created for an index out of range, which goes in the default universe,
because there is no source element.
Another exception is a fold operation on a container, which is given a