## Problem 246 — rank:256

**Title:** Causes of rising early-onset cancers

**Added binding assumptions (LaTeX):**

```latex
The age--period--cohort linear-trend invariance is established algebra, with additional constant-offset redundancies. Only transformations remaining inside the spline and bounded-parameter class are admissible. Identifying constraints choose a representative and do not reveal the true causal decomposition. Curvature is identifiable only to the extent the design and ascertainment restrictions support it; an unrestricted $q_{ap}$ can absorb changes beyond the usual linear ambiguity.
```

**Direct edits:** 0. **Fresh external checks:** None; supplied sources retained as provenance.