s
\(i\) in categories \(h\) and classes \(j\). The item response model is
$$P( X_{i}=h | j )=\frac{ \exp( x_{ihj} ) }{ \sum_l \exp( x_{ilj} ) }$$
with linear constraints on the class specific probabilities
$$  x_{ihj}=\sum_v  q_{ihjv} \lambda_{xv} $$</p>
<p>Linear restrictions on the \(\lambda_x\) parameter can be specified by
a matrix equation \(V_x \lambda_x=c_x\) (see <code>Xlambda.constr.V</code> and
<code>Xlambda.constr.c</code>; Neuhaus, 1996).</p>
<p>The latent class distribution can be smoothed by a