GATE D32
Implicit realizability and the symbolic CEGAR kernel: PARTIAL
What changed
D32 tests the remaining unrefuted route, representing the global realizability problem implicitly and refining it with exact predicates rather than enumerating any product of local states. The scan defines an abstraction-refinement loop whose predicates, local admissibility, the top-coefficient square lift, positivity and Newton inequalities, and square splitting, are each proved to preserve every governed tuple, and on complete finite domains the loop agrees with brute-force enumeration, including a case where square splitting is the load-bearing refinement. Phase 1 implements a genuinely symbolic kernel with two independent exact backends, a canonical reduced decision diagram and an independent finite-domain engine. The local admissibility layer compresses genuinely: the diagram uses a number of nodes linear in the prime count while representing the full product, with zero Cartesian materialization. The coupling constraint does not compress in the implemented backends, because its construction materializes a bounded-square or product enumeration, so the cost moves to preprocessing. The local-separability result is a proved theorem; the coupled layer is a representation-specific obstruction, not a universal one. LRC(13) remains open.
Evidence
Verification: double · I2 · 6 artifacts (reports, verifiers, corruption suites, manifest with SHA-256)