# PH-RES-001

**Name:** Residual exceeds variationally-correct norm threshold

**Severity:** error

**Input modes:** adapter+dump

PH-RES-001 is a two-path characterization of the rule's residual norm
behavior along two dimensions: spatial convergence (on a refined
sequence of grids) and norm equivalence (between physics-lint's emitted
quantity and a reference norm). The rule is calibrated against
Fornberg 1988 (finite-difference stencil rates) and the
Bachmayr-Dahmen-Oster / Ernst et al. variational-correctness framework;
see `CITATION.md` for the full four-layer structure and provenance.