The definition of node expressions with lists is based on sequences of nodes.

The naming of operations, however, is set-style.

If the processing model is to be list based, then naming might reflect that:

• sh:union => sh:sequenceOf or sh:concat or sh:join
• sh:minus => sh:remove

A natural step is then whether the usual operations on sequences sh:flatmap, sh:findFirst, sh:matchAll are needed.