From: Tobias Nipkow <nipkow@in.tum.de>
In your second proof you have a free f that needs to be fixed. In
particular, you need to ensure that the type of f and of x and y fit
together. You should start with
fix f :: "'a" and x y :: "'a tree"
(I haven't tried it out...)
But writing all of this out by hand is painful. I recommend to use the
case (Node x f y)
...
show ?case
idiom to simplify your life.
Tobias
张欢欢 schrieb:
Last updated: Nov 21 2024 at 12:39 UTC