@defun cl-reduce function seq @t{&key :from-end :start :end :initial-value :key}
This function returns the result of calling @var{function} on the
-first and second element of @var{seq}, then calling @var{function}
+first and second elements of @var{seq}, then calling @var{function}
with that result and the third element of @var{seq}, then with that
-result and the third element of @var{seq}, etc.
+result and the fourth element of @var{seq}, etc.
Here is an example. Suppose @var{function} is @code{*} and @var{seq}
is the list @code{(2 3 4 5)}. The first two elements of the list are