2 | 12. x2: x,y:Alph*//(x R y) 13. x3: x,y:Alph*//(x R y) 14. y1: Alph* 15. u: Alph 16. v: Alph* 17. ( < (x,y:Alph*//(x R y)) (x,y:Alph*//(x R y)), a,p. p/x,y. < a.x,a.y > > :v < x2,x3 > )
=
( < x2,x3 > /x1,x2. < v@ x1,v@ x2 > ) (( < (x,y:Alph*//(x R y)) (x,y:Alph*//(x R y)), a,p. p/x,y. < a.x,a.y > > :v < x2,x3 > )/x,y. < u.x,u.y > )
=
< u.(v @ x2),u.(v @ x3) >
(x,y:Alph*//(x R y)) (x,y:Alph*//(x R y)) |