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\section{library(semweb/rdf_compare): Compare RDF graphs}

\label{sec:rdfcompare}

This library provides predicates that compare RDF graphs. The current
version only provides one predicate: \predref{rdf_equal_graphs}{3} verifies that
two graphs are identical after proper labeling of the blank nodes.

Future versions of this library may contain more advanced operations,
such as diffing two graphs.\vspace{0.7cm}

\begin{description}
    \predicate[semidet]{rdf_equal_graphs}{3}{+GraphA, +GraphB, -Substition}
True if \arg{GraphA} and \arg{GraphB} are the same under \arg{Substition}.
\arg{Substition} is a list of BNodeA = BNodeB, where BNodeA is a blank
node that appears in \arg{GraphA} and BNodeB is a blank node that
appears in \arg{GraphB}.

\begin{arguments}
\arg{GraphA} & is a list of \verb$rdf(S,P,O)$ terms \\
\arg{GraphB} & is a list of \verb$rdf(S,P,O)$ terms \\
\arg{Substition} & is a list if NodeA = NodeB terms. \\
\end{arguments}

\begin{tags}
    \tag{To be done}
The current implementation is rather naive. After
dealing with the subgraphs that contain no bnodes,
it performs a fully non-deterministic substitution.
\end{tags}
\end{description}