Recursive definition of loghead.
Theorem:
(defthm loghead* (implies (loghead-guard size i) (equal (loghead size i) (if (equal size 0) 0 (logcons (logcar i) (loghead (1- size) (logcdr i)))))) :rule-classes ((:definition :clique (loghead$inline) :controller-alist ((loghead$inline t t)))))