I am listening to Markus video about indexing  and might have an epiphany …
Markus enumerates a number of techniques to help first argument indexing in determining when a clause is selected deterministically and without choice points.
One technique relates to pulling into, or rearranging the head to help the indexing identify that two clauses don’t equally unify.
So, i am now wondering with SSU and guards – is it now the guard that unequivocally determines which clause is selected deterministically and hence without choice point – (unless, the body reintroduces one?).
So, if the structure of guards make clauses distinguishable, then no choice point is created?