## Problem 236 — rank:254

**Title:** Tissue-resident immune memory

**Added binding assumptions (LaTeX):**

```latex
The density ratio can exceed one and is not a probability; label it a maintenance ratio. Predicting lineage survival requires an individual birth, division, death and recruitment law, not only the net density ODE. Specify the conditioning state and observation error in the denominator. Equal net counts are compatible with arbitrarily different turnover rates unless independent labels or equivalent information constrain them.
```

**Direct edits:** 2. **Fresh external checks:** None; supplied sources retained as provenance.