Part XIV: Semantics

This part records the technical semantics of Predica. Earlier parts introduce the motivation, examples, query notation, and relation views; this part gives the denotational account those explanations rely on.

The current query account is logic-first. Predica query expressions denote logic frames. Relation-shaped results are extensional observations of those frames under headings, as described in the Relations part.

Location denotation is a second, partial denotation for expressions that can be used as update targets. It records writable places while retaining the address witnesses needed to perform writes. It is interpreted under the schema constraints, which determine when paths reach shared entity occurrences and therefore denote the same location. Reading the locations selected by an expression agrees with the expression's ordinary query-frame denotation. This relationship gives updates a precise meaning without identifying locations with the values currently stored at them.