; @origtpdbfilename ./TRS/Zantema/z21.trs
; @xtcfilename "./TRS_Standard/Zantema_05/z21.xml"
(format TRS)
(fun f 2)
(fun a 0)
(fun b 0)
(rule (f (f a b) x) (f a (f a x)))
(rule (f (f b a) x) (f b (f b x)))
(rule (f x (f y z)) (f (f x y) z))