and tt tt tt is_nat 0 tt is_nat s x is_nat x is_natlist nil tt is_natlist cons x xs and is_nat x is_natlist xs from x fromCond is_natlist x x fromCond tt cons x xs from cons s x cons x xs and 2 tt 0 is_nat 1 0 0 s 1 is_natlist 1 nil 0 cons 2 from 1 fromCond 2 FULL TRS//AProVE_10/challenge_fab.trs