TREE AUTOMATA AND AUTOMATAON LINEAR ORDERI NGS

We sh ow t h at t h e i n c lu sion p r ob lem i s d ecid ab le for r at io-n al lan gu ages of word s in d e x e d by scat t e red c ou nt ab le lin ear ord erin gs.Th e m et h o d lean s on a r ed u c t ion t o t h e d ecid ab ility of t h e mon ad ic sec-on d order theory of the infinite binary tree