## Problem 146 — rank:89

**Title:** Rate of reproductive-isolation evolution

**Added binding assumptions (LaTeX):**

```latex
An isolation index confined to $[0,1]$ needs a bounded observation model, such as a binomial-stage or beta model, rather than unrestricted additive noise on the probability scale. State how uncertain divergence times and phylogenetic dependence enter the likelihood. Monotone accumulation is a testable model restriction, not a definition that can rule out genuine barrier weakening by construction.
```

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