## Problem 073 — rank:323

**Title:** Spatial-transcriptomic deconvolution

**Added binding assumptions (LaTeX):**

```latex
The maximization returns a pair $(\widehat A,\widehat C)$, as corrected. Fix dispersion parameters, signature scaling and capture factors, or estimate them jointly under constraints that remove their scaling symmetries. Full-rank known signatures and identifiable anchored unknown signatures are different alternatives. The relative error criterion presumes $\|C_0\|_F>0$ and must be weakened where rare types are below detection.
```

**Direct edits:** 1. **Fresh external checks:** None; supplied sources retained as provenance.