## Problem 071 — rank:224

**Title:** Cell-state trajectory inference

**Added binding assumptions (LaTeX):**

```latex
Specify the survival and lineage-sampling rule in the transition kernel, including whether a random daughter or a size-biased descendant is followed. For a continuous starting state, $K_{s,t}$ is the regular conditional kernel supplied by the model; empirical validation needs a supported neighborhood or controlled initial-state preparation. Reproducing marginal snapshots is strictly weaker than identifying this kernel.
```

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