KERML_ — Impossible to specialize (redefine, subset) unnamed features in textual syntax

Since unnamed features cannot be referred to by name, there is no textual syntax to specialize them in a type subtyping the featuring type, even though the abstract syntax can express this relationship.

Specialization is key in execution, where our current approach is to specialize and restrict user-defined types to a model that has a single (family of) interpretations, which is included in the set of original interpretatios (see Annex A). This involves redefining and subsetting the user-defined type's features.

Based on the above, we can conclude that there is currently no way to describe an execution trace in the textual syntax for a model which contains unnamed elements.