 The hyperintensionality of the \(\lambda\)-calculus is particularly important when it comes to its applications as a theory of not only functions, but more generally \(n\)-ary relations. On this, see section  9.3.  It is effectively the hyperintensionality of the \(\lambda\)-calculus that makes it an attractive tool in this context. It should be noted, however, that the \(\lambda\)-calculus can be made extensional (as well as intensional) by postulating additional laws concerning the equality of \(\lambda\)-terms. On this, see section  5.