*/
    Map<MetadataGraphVertex, List<MetadataGraphEdge>> incidentEdges;

    Map<MetadataGraphVertex, List<MetadataGraphEdge>> excidentEdges;

    /**
     *  null in dirty graph, actual
     *  scope for conflict-resolved graph
     */
    ArtifactScopeEnum scope;

    // ------------------------------------------------------------------------
    /**
     * init graph
     */
    public MetadataGraph(int nVertices) {