Commit 6a439a53 authored by Adam Chlipala's avatar Adam Chlipala

Coinductive exercise description

parent 36f51ef2
......@@ -455,3 +455,19 @@ End constFold_ok.
(** If we print the proof term that was generated, we can verify that the proof is structured as a [cofix], with each co-recursive call properly guarded. *)
Print constFold_ok.
(** * Exercises *)
(** %\begin{enumerate}%#<ol>#
%\item%#<li># %\begin{enumerate}%#<ol>#
%\item%#<li># Define a co-inductive type of infinite trees carrying data of a fixed parameter type. Each node should contain a data value and two child trees.#</li>#
%\item%#<li># Define a function [everywhere] for building a tree with the same data value at every node.#</li>#
%\item%#<li># Define a function [map] for building an output tree out of two input trees by traversing them in parallel and applying a two-argument function to their corresponding data values.#</li>#
%\item%#<li># Define a stream [falses] where every node has the value [false].#</li>#
%\item%#<li># Define a stream [true_false] where the root node has value [true], its children have value [false], all nodes at the next have the value [true], and so on, alternating boolean values from level to level.#</li>#
%\item%#<li># Prove that [true_falses] is equal to the result of mapping the boolean "or" function [orb] over [true_false] and [falses]. You can make [orb] available with [Require Import Bool.]. You may find the lemma [orb_false_r] from the same module helpful. Your proof here should not be about the standard equality [=], but rather about some new equality relation that you define.#</li>#
#</ol>#%\end{enumerate}% #</li>#
#</ol>#%\end{enumerate}% *)
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