The incremental specifications must be consistent, so that they can be synthesized into an integrated solution.

We need to verify that the incremental specifications are consistent, by checking (a) the C-cards are consistent, (b) the I-cards are consistent, and (c) the cards can be integrated.

(a) Two C-cards are consistent, if either (i) the node names and arc names are disjoint, or (ii) the node names and arc names are not disjoint, and the overlapped sub-nets are identical.