The list summation task in the post is just a list reduction, and a reduction can automatically be parallelized for any associative operator. The gory parallelization details in the post are only something the user needs to care about in a purely imperative language that lacks native array operations like reduction. In an array language, the `reduce` function can detect whether the reduction operator is associative and if so, automatically handle the parallelization logic behind-the-scenes. Thus `reduce(values, +)` and `reduce(values, *)` would execute seamlessly without the user needing to explicitly implement the exact subdivision of work. On the other hand, `reduce(values, /)` would run in serial, since division is not associative. Custom binary operators would just need to declare whether they're associative (and possibly commutative, depending on how the parallel scheduler works internally), and they'd be parallelized out-of-the-box.