## Problem 208 — rank:173

**Title:** Epidemiological consequences of immune escape

**Added binding assumptions (LaTeX):**

```latex
Require $0\leq C_{jk}\leq1$ for the multiplicative susceptibility model and specify all history-reset transitions. The closed probability equations are a mean-field population model with nonlinear dependence on $i_j$; a finite-host stochastic epidemic instead needs a joint count-process law and does not generally close at its marginal means. Treat multiplicative cross-protection and one-current-category infection as restricted hypotheses, not universal immune-history identities.
```

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