(build-elitegroups pop-agents argmap)
Builds a sequence that partitions the cases into sub-sequences, with cases grouped when they produce the same set of elite individuals in the population. In addition, if group A produces population subset PS(A), and group B produces population subset PS(B), and PS(A) is a proper subset of PS(B), then group B is discarded.
(elitegroup-lexicase-selection pop argmap)
Returns an individual produced by elitegroup lexicase selection.