1 | 13. TBL: ((x,y:Alph*//(x R y)) (x,y:Alph*//(x R y)))* 14. s:((x,y:Alph*//(x R y)) (x,y:Alph*//(x R y))).
mem_f((x,y:Alph*//(x R y)) (x,y:Alph*//(x R y));s;TBL)

( w:Alph*.
mem_f((x,y:Alph*//(x R y)) (x,y:Alph*//(x R y));( < (x,y:Alph*//(x R y)) (x,y:Alph*//(x R y))
, a,xy. xy/x,y. < a.x,a.y > > :w s);fL)) 15. x: x,y:Alph*//(x R y) 16. y: x,y:Alph*//(x R y) Dec(x Rg y) |