Theorem

FPRD-T51

Exact profiles for depth thresholds

Exact statement

For generalized-Dyck words whose stack height reaches at least r≥1r\ge1, qk,r≥(N)=1+∑h=0Nkh+∑h=max⁡(0,2r−N)r−1khq_{k,r}^{\ge}(N)=1+\sum_{h=0}^{N}k^h+\sum_{h=\max(0,2r-N)}^{r-1}k^h and ak,r≥(N)=max⁡(2r,N)a_{k,r}^{\ge}(N)=\max(2r,N). For words staying below (r), qk,r<(N)=1+∑h=0min⁡(N,r−1)khq_{k,r}^{<}(N)=1+\sum_{h=0}^{\min(N,r-1)}k^h and ak,r<(N)=max⁡(1,min⁡(N,r−1))a_{k,r}^{<}(N)=\max(1,\min(N,r-1)).

StatusProved and internally audited
External reviewNo documented external or specialist review of this FPRD result is recorded.

Context

These families isolate the cost of remembering whether a nesting threshold has been crossed while retaining the exact typed stack.

Definitions

  • Dk,ℓ≥rD_{k,\ell}^{\ge r} contains balanced words whose stack reaches height at least r.
  • Dk,ℓ<rD_{k,\ell}^{<r} is the complementary below-threshold branch inside the Dyck language.

Hypotheses and scope

  • Bracket rank k and threshold r are positive integers.

Proof or evidence

Post-threshold rows are indexed by visible typed stacks. A pre-threshold stack of height h becomes visible exactly when the horizon reaches 2r-h. Shortest height paths give the access formulas.

Verification notes

All pre/post, typed-stack, cross-height, horizon-zero, threshold-one, and neutral-symbol cases were checked in the proof and independent enumerations.

Limitations

  • A fixed horizon-zero row count of two does not bound access across the family: the value 2r is unbounded.
  • The theorem makes no novelty claim.

Open work

Use the threshold families as calibrations when comparing access certificates across equivalent controllers.

Notes

This is an exact finite-controller family theorem. It does not imply that scalar count determines access, and it makes no novelty claim.