Boundary result · unbounded parameter gap

FPRD-SH-B10

Diversity can overestimate the best intersecting-core kernel without bound

Exact statement

For every prime power qq, the line supports of PG(2,q)PG(2,q) are pairwise intersecting, so κ=0\kappa=0. There are q2+q+1q^2+q+1 supports and every participant lies on q+1q+1 of them, so closest-star diversity is γ=q2\gamma=q^2. Thus γ−κ\gamma-\kappa is unbounded within the intersecting-core decomposition.

StatusSelf-contained finite-geometry proof; exact q=2,3,5 controls pass
External reviewNo documented external or specialist review of these FPRD results is recorded.

Context

Large intersecting families need not have a common participant.

Proof or evidence

Projective-plane lines form a complete intersecting core while every participant star omits q squared lines.

Verification notes

Exact incidence constructions give (gamma,kappa)=(4,0),(9,0),(25,0).

Limitations

  • The projective-plane family uses growing uniformity.
  • This is a correction, not a new finite-geometry theorem.

Open work

Do not describe diversity as a complete or optimal search kernel.