## Problem 126 — rank:84

**Title:** Mechanics of gastrulation

**Added binding assumptions (LaTeX):**

```latex
Compare velocities after a specified registration or pullback between observed and predicted moving domains, using a fixed volume-weighted norm. Close the mechanical model with material state, constitutive law, boundary tractions and division rules. Add a geometric or topology criterion when correct folding is claimed: small velocity error on a short interval alone does not certify the final tissue arrangement.
```

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