ex-transform.section" class="section level2">
<h2><span class="header-section-number">10.7</span> Unit Simplex</h2>
<p>Variables constrained to the unit simplex show up in multivariate
discrete models as both parameters (categorical and multinomial) and
as variates generated by their priors (Dirichlet and multivariate
logistic).</p>
<p>The unit <span class="math inline">\(K\)</span>-simplex is the set of points <span class="math inline">\(x \in \mathbb{R}^K\)</span> such that
for <span class="math inline">\