(VAR x) (RULES rec(rec(x)) -> sent(rec(x)) rec(sent(x)) -> sent(rec(x)) rec(no(x)) -> sent(rec(x)) rec(bot) -> up(sent(bot)) rec(up(x)) -> up(rec(x)) sent(up(x)) -> up(sent(x)) no(up(x)) -> up(no(x)) top(rec(up(x))) -> top(check(rec(x))) top(sent(up(x))) -> top(check(rec(x))) top(no(up(x))) -> top(check(rec(x))) check(up(x)) -> up(check(x)) check(sent(x)) -> sent(check(x)) check(rec(x)) -> rec(check(x)) check(no(x)) -> no(check(x)) check(no(x)) -> no(x) )