\section{Introduction}
\label{sec:intro}
-\MATITA{} is the Proof Assistant under development by the \HELM{}
+\MATITA is the Proof Assistant under development by the \HELM{}
team~\cite{mkm-helm} at the University of Bologna, under the direction of
-Prof.~Asperti. This paper describes the overall architecture of
-the system, focusing on its most distinctive and innovative
+Prof.~Asperti. \MATITA{} is free software, the source code is available for
+download at \url{http://matita.cs.unibo.it}. This paper describes the overall
+architecture of the system, focusing on its most distinctive and innovative
features.
\subsection{Historical perspective}
occurrence.
At this point, since \COQ{} unification algorithm is essentially first-order,
-the application of an elimination principle (of the form $\forall P.\forall
+the application of an elimination principle (a term with type $\forall P.\forall
x.(H~x)\to (P~x)$) will unify \texttt{x} with \texttt{n} and \texttt{P} with
\texttt{(fun n0: nat => m + n = n0)}.
revision control system, building on the invalidation and re-generation
concepts already implemented to grant logical consistency.
-Thanks to an increasing dissemination activity, we hope in the medium
+Thanks to an increasing dissemination activity, we hope in the\linebreak medium
term to attract users to form a critical mass of users to enter in
direct competition with the (still too few) major actors in the field.
To this aim, we are also progressing in the development of a core library,