Warning 3.1.6.24. The collection of weak homotopy equivalences is not closed under the formation of infinite products. For example, if $q: G \rightarrow \Delta ^0$ is the weak homotopy equivalence described in Exercise 3.1.6.21, then a product of infinitely many copies of $q$ with itself is not a weak homotopy equivalence (since a product of infinitely many copies of $G$ is not a connected simplicial set: see Warning 1.2.1.28).
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$