The power set of a finite set is used as the alphabet of astring interpreting a sentence of Monadic Second-Order Logic so thatthe string can be reduced (in a straightforward way) to the symbolsoccurring in the sentence. Simple extensions to regular expressionsare described matching the succinctness of Monadic Second-OrderLogic. A link to Goguen and Burstall’s notion of an institution isforged, and applied to conceptions within natural language semanticsof time based on change.