+ x 0 x + 0 x x + s x s y s s + x y + + x y z + x + y z * x 0 0 * 0 x 0 * s x s y s + * x y + x y * * x y z * x * y z app nil l l app cons x l1 l2 cons x app l1 l2 sum nil 0 sum cons x l + x sum l sum app l1 l2 + sum l1 sum l2 prod nil s 0 prod cons x l * x prod l prod app l1 l2 * prod l1 prod l2 2.2 sum app l1 l2 sum l1 * s x s y + * x y + x y + s x s y + x y app cons x l1 l2 app l1 l2 prod app l1 l2 prod l1 prod app l1 l2 prod l2 * * x y z * x * y z * s x s y * x y prod app l1 l2 * prod l1 prod l2 sum cons x l sum l prod cons x l prod l + + x y z + y z prod cons x l * x prod l sum app l1 l2 sum l2 sum app l1 l2 + sum l1 sum l2 * s x s y + x y * * x y z * y z sum cons x l + x sum l + + x y z + x + y z true app cons x l1 l2 app l1 l2 true prod 1 0 s 1 0 prod 1 0 * 2 0 sum 1 0 0 0 0 nil 0 0 app 2 1 0 cons 2 2 1 + 2 0 sum 1 0 + 2 0 * 2 0 app 2 0 prod app l1 l2 prod l2 prod app l1 l2 prod l1 prod cons x l prod l true prod 1 0 s 1 0 prod 1 1 0 * 2 0 sum 1 0 0 0 0 nil 0 0 app 2 0 cons 2 2 1 + 2 0 sum 1 0 + 2 0 * 2 0 app 2 1 2 1 prod cons x l * x prod l false prod app l1 l2 * prod l1 prod l2 false * * x y z * x * y z * * x y z * y z * s x s y * x y true prod 1 0 s 1 1 1 prod 1 0 * 2 1 0 sum 1 0 0 0 1 nil 0 0 app 2 0 cons 2 1 + 2 1 2 1 sum 1 0 + 2 0 * 2 1 2 2438 app 2 1 * s x s y + * x y + x y false * s x s y + x y false sum app l1 l2 sum l2 sum cons x l sum l sum app l1 l2 sum l1 true prod 1 0 s 1 1 1 prod 1 0 * 2 0 sum 1 0 0 0 1 nil 0 0 app 2 0 cons 2 2 1 + 2 1 2 8366 sum 1 1 0 + 2 0 * 2 1 2 2438 app 2 1 2 1 sum app l1 l2 + sum l1 sum l2 false sum cons x l + x sum l false + + x y z + x + y z + s x s y + x y + + x y z + y z true prod 1 0 s 1 1 1 prod 1 0 * 2 0 sum 1 0 0 0 28382 nil 0 0 app 2 0 cons 2 1 + 2 1 2 1143 sum 1 0 + 2 1 0 * 2 1 2 1 app 2 1 + + x y z + x + y z + x 0 x + s x s y s s + x y + 0 x x NaTT certifiable-1.6