Theorem · spectral collision and overhead lower bound

FPRD-SH-T23

The Kneser spectrum gives an above-threshold overhead receipt

Exact statement

Assume 1≤r≤n/21\leq r\leq n/2. Let N=(nr)N=\binom nr, d=(n−rr)d=\binom{n-r}r, τ=(n−r−1r−1)\tau=\binom{n-r-1}{r-1}, and α=(n−1r−1)\alpha=\binom{n-1}{r-1}. If an rr-uniform policy has m>αm>\alpha supports, then its number of disjoint pairs is at least ⌈d+τ2Nm(m−α)⌉\left\lceil\frac{d+\tau}{2N}m(m-\alpha)\right\rceil. The depth-one one-shot overhead dominates this count.

StatusSelf-contained spectral derivation from the known Kneser spectrum; exact finite audit passes
External reviewNo documented external or specialist review of these FPRD results is recorded.

Context

EKR says a collision must occur above the independent-set ceiling; the spectral calculation counts a forced first layer of collision witnesses.

Proof or evidence

The least Kneser eigenvalue bounds the induced edge count. Every induced edge is a size-two support matching, and FPRD-SH-T20 makes that a unit contribution to one-shot overhead.

Verification notes

The rational inequality passes on every complete small-domain family and on 640 deterministic larger policies covering 10,466 matching states.

Limitations

  • The bound is not claimed sharp; stronger supersaturation theorems are known in restricted parameter ranges.
  • It requires 1<=r<=n/2 and lower-bounds the one-shot witness family, not the overhead of every expression tuple.
  • The spectral argument is classical framework synthesis, not a new Kneser-graph theorem.

Open work

Replace the general spectral receipt with the exact diversity and supersaturation hierarchy in its valid parameter ranges.