\section{Bool}\label{Bool} The BOOL library includes the following files: \begin{itemize} \item {\tt Bool.v} defines standard operations on booleans and states and proves simple facts on them. \item {\tt IfProp.v} defines a disjunction which contains its proof and states its properties. \item {\tt Zerob.v} defines the test against 0 on natural numbers and states and proves properties of it. \item {\tt Orb.v} states and proves facts on the boolean or. \item {\tt DecBool.v} defines a conditional from a proof of decidability and states its properties. \end{itemize}