italic; font-weight: bold;">L</span>) is
the class of models for the language, and the collection of types
<span style="font-family: arial; font-style: italic;">expr</span>(<span
 style="font-style: italic; font-weight: bold;">L</span>) is the set of
expressions for the language. Lattice order is
reverse subset inclusion on the theorem sets of closed theories. The
instance embedding function <span
 style="font-family: arial; font-style: italic;">max-th</span>(<span
 style="font-style: italic; font-weight: b