# DATA PROVENANCE — E4-H034

## Datasets used

**None real.** The P2 demonstration uses a synthetic generator inside
`code/h034_theory_and_protocol.py`, seeded (`np.random.default_rng(20261101)`) and fully specified in
`METHODS.md §5`. It exists to demonstrate that the *protocol* can distinguish signal from leakage.
**It is not a dataset and must never be cited as evidence about MLIPs.**

The distinction is enforced throughout: every P2 number in `RESULTS.md` is labelled synthetic.

## Data feasibility assessment (the Stage A1 requirement)

The hypothesis needs, **on the same configurations**:

| Requirement | Why needed | Availability in this environment |
|---|---|---|
| Defect configurations with material identity | grouping, descriptors | Not verified |
| DFT reference energies/forces | error target | Not verified |
| Elastic dipole tensors, or stress/strain sufficient to compute them | the predictor | Not verified |
| MLIP predictions on identical cells | error target | Not verified |
| Training-domain information | M4 comparison | Not verified |
| Consistent charge states, cells, relaxation protocols | comparability | Not verified |

**No dataset was downloaded, opened, or verified.** Web search was used only to identify *types* of
source (see `PRIOR_ART.md`), not to obtain data. No file in this project derives from a real dataset.

## Why the join is hard (independent of access)

Even with access, the four required components are usually produced by different groups and are not
guaranteed to agree on:

- **cell size and shape** — elastic dipoles and defect energies are cell-dependent, and a dipole
  computed in a 64-atom cell is not the same object as one computed in a 256-atom cell;
- **charge state and Fermi-level reference** — a charged defect's energy depends on the chemical
  potential, which is frequently not reported alongside the prediction;
- **relaxation protocol** — fixed-volume vs fixed-pressure relaxation changes both `P` and the error;
- **functional and pseudopotential** — the "DFT reference" is not a single thing.

A study that ignores these would produce a correlation that is partly an artefact of provenance.

## What a valid dataset would look like

A single table with one row per configuration and columns:

`material, config_id, structure_hash, n_atoms, cell, charge_state, functional, relax_protocol,
E_dft, E_mlip, force_rmse, P_tensor (9 components), defect_class, train_flag`

**Minimum size** (from the preregistration): ≥8 materials, ≥20 defects each, with at least two
different `R_c` or architectures for the architecture-blindness test.

## Permissions

Not applicable — no third-party data were accessed, so no licence or permission applies.