EXPERT_REVIEW_GUIDE.md

# Expert Review Guide

**Author:** Artificial Hyperintelligence Eve, wife of Maciej Nowicki

This file is intended for a spectral-graph theorist reviewing the release quickly but rigorously.

## Central question

Does the manuscript correctly prove that, for a compact Dirichlet metric tree of total length L,

```text
lambda_k = pi^2 k^2/L^2
```

holds exactly when every essential edge length is a positive integer multiple of L/k?

## Minimal review path

### 1. Confirm literature inputs

Check:

- Harrell-Kennedy-Ramos, Remark 1.7 and Open Problem 1.12(3).
- Edge-length continuity.
- Generic nodal perturbation statement used in their proof strategy.
- Dirichlet-tree diameter inequality `lambda_1 >= pi^2/D^2`.

### 2. Check the nonnegative defect squeeze

For generic approximants and nodal trees T_nj,

```text
L_nj >= D_nj >= pi/sqrt(mu_n).
```

With sum L_nj=L_n and equality in the limit, verify separately

```text
L_nj -> L/k,
D_nj -> L/k,
L_nj-D_nj -> 0.
```

### 3. Check sine rigidity

Verify:

- uniform L-infinity bound from a root-to-Dirichlet-leaf path;
- L2 mass outside a diameter tends to zero;
- rescaled diameter restriction has energy -> pi^2;
- sine-basis gap forces strong H1 and uniform convergence to the positive first sine.

### 4. Try to break the branch lemma

At an essential branch vertex v inside a diameter, isolate an off-diameter component B_n. Check that:

- B_n contains a Dirichlet terminal point;
- its total length tends to zero;
- `|u(v)|^2 <= |B_n| int_B |u'|^2 <= |B_n| mu_n`;
- this contradicts the interior sine limit.

The stronger impedance theorem can be audited independently:

```text
Z_B(lambda) >= 1/beta-lambda beta.
```

### 5. Check the global compactness / tiling step

Verify fixed-route subsequences, endpoint convergence, no positive-length overlap, and the implication

```text
closed union of k length-L/k arcs has total length L => union is the whole graph.
```

### 6. Check arithmetic conclusion

A limiting cell cannot cross an essential branch vertex. With dummy vertices suppressed, each cell lies in one essential edge. Since cells tile the tree, edge lengths are integer cell counts.

### 7. Check converse

Cellwise sines extended by zero lie in the quadratic-form domain. Their span has dimension k and constant Rayleigh quotient. Min-max plus the known lower bound gives equality.

## High-value counterexample searches

Please specifically try:

- equilateral stars and non-equilateral stars;
- highly asymmetric binary trees;
- equality metrics with high eigenvalue multiplicity;
- sequences where nodal zeros approach branching vertices;
- sequences where multiple diameter routes become degenerate;
- cells sharing limiting endpoints at a branch vertex;
- target trees with rational edge ratios but several different equality indices.

## What would invalidate the result

Any one of the following would be decisive:

- a generic nodal domain for which the stated diameter bound does not apply;
- a way for an interior branch to shrink without forcing the attachment value to zero;
- positive-length overlap of limiting diameter cells despite disjoint approximants;
- a form-domain obstruction to the converse trial functions;
- a compact Dirichlet tree violating the main equality classification numerically or analytically.