An Algebraic Graph Transformation Approach for RDF and SPARQL

TL;DR

This paper introduces a formal algebraic framework based on category theory for RDF and SPARQL, clarifying their features and semantics through graph transformations, especially focusing on blank nodes and query operations.

Contribution

It presents a novel algebraic graph transformation approach, POIM, providing formal definitions and semantics for RDF graphs and SPARQL queries using category theory.

Findings

Formal definitions of RDF graphs and SPARQL patterns

Clarification of blank nodes' roles in RDF

Operational semantics for SPARQL queries using POIM

Abstract

We consider the recommendations of the World Wide Web Consortium (W3C) about RDF framework and its associated query language SPARQL. We propose a new formal framework based on category theory which provides clear and concise formal definitions of the main basic features of RDF and SPARQL. We define RDF graphs as well as SPARQL basic graph patterns as objects of some nested categories. This allows one to clarify, in particular, the role of blank nodes. Furthermore, we consider basic SPARQL CONSTRUCT and SELECT queries and formalize their operational semantics following a novel algebraic graph transformation approach called POIM.