\f z. f a (f b (f c z))
-Here we work with curried functions, because as we explained at the end of the section on Tuples, that's the idiomatic and native style for passing multiple arguments in the Lambda Calculus.
+Here we assume `f` to be a curried function, taking its arguments in the form `f c z` rather that `f (c, z)` (that is, `f (\h. h c z)`), because as we explained at the end of the section on Tuples, the curried form is the idiomatic and native style for passing multiple arguments in the Lambda Calculus.
So if `[a, b, c]` should be the displayed higher-order function above, what should `[c]` be? Evidently: