# VWDC-05 — Reality-Tethered World Calibration, Transport Contracts, and External Validity

## Core object

$$
\boxed{
\mathsf{RTC}_Q
=
(
Q,
\mathcal Z,
\nu_W,
\nu_R,
T_Q,
\mathcal V,
\mathcal A,
\Delta_Q,
\mathcal D_{\mathrm{ext}},
\mathsf{Expiry},
\mathsf{Prov}
).
}
$$

## Core validation warning

$$
\boxed{
\text{marginal agreement}
\not\Rightarrow
\text{conditional validity}.
}
$$

## Counterfactual warning

$$
\boxed{
\text{correct potential-outcome marginals}
\not\Rightarrow
\text{identified joint counterfactual coupling}.
}
$$

## Complete comparison debt

$$
\boxed{
D
=
D_{\mathrm{world}}
+
D_{\mathrm{transport}}
+
D_{\mathrm{measurement}}.
}
$$

## Canonical rule

External validity is a maintained, claim-specific, region-specific, version-specific transport contract.

## Package contents

- canonical paper;
- literature audit;
- roadmap;
- VWDC-06 handoff;
- theorem index;
- tests;
- validation;
- checksums.