## Problem 155 — rank:155

**Title:** Evolution of mutual dependence

**Added binding assumptions (LaTeX):**

```latex
An all-positive-invasion deletion path is a restricted adaptive route, not every route with positive fixation probability under drift. Define partner-free dependence relative to the dilution or mortality threshold rather than an impossible negative gross birth rate. Verify coexistence stability in the complete ecological state and test a declared invader class; positive equilibrium densities alone establish neither dynamical stability nor resistance to replacement.
```

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