--- a/doc-src/IsarRef/Thy/HOL_Specific.thy Wed Oct 15 19:43:11 2008 +0200
+++ b/doc-src/IsarRef/Thy/HOL_Specific.thy Wed Oct 15 21:06:15 2008 +0200
@@ -775,6 +775,90 @@
*}
+section {* Invoking automated reasoning tools -- The Sledgehammer *}
+
+text {*
+ Isabelle/HOL includes a generic \emph{ATP manager} that allows
+ external automated reasoning tools to crunch a pending goal.
+ Supported provers include E\footnote{\url{http://www.eprover.org}},
+ SPASS\footnote{\url{http://www.spass-prover.org/}}, and Vampire.
+ There is also a wrapper to invoke provers remotely via the
+ SystemOnTPTP\footnote{\url{http://www.cs.miami.edu/~tptp/cgi-bin/SystemOnTPTP}}
+ web service.
+
+ The problem passed to external provers consists of the goal together
+ with a smart selection of lemmas from the current theory context.
+ The result of a successful proof search is some source text that
+ usually reconstructs the proof within Isabelle, without requiring
+ external provers again. The Metis
+ prover\footnote{\url{http://www.gilith.com/software/metis/}} that is
+ integrated into Isabelle/HOL is being used here.
+
+ In this mode of operation, heavy means of automated reasoning are
+ used as a strong relevance filter, while the main proof checking
+ works via explicit inferences going through the Isabelle kernel.
+ Moreover, rechecking Isabelle proof texts with already specified
+ auxiliary facts is much faster than performing fully automated
+ search over and over again.
+
+ \begin{matharray}{rcl}
+ @{command_def (HOL) "sledgehammer"}@{text "\<^sup>*"} & : & \isarkeep{proof} \\
+ @{command_def (HOL) "print_atps"}@{text "\<^sup>*"} & : & \isarkeep{theory~|~proof} \\
+ @{command_def (HOL) "atp_info"}@{text "\<^sup>*"} & : & \isarkeep{\cdot} \\
+ @{command_def (HOL) "atp_kill"}@{text "\<^sup>*"} & : & \isarkeep{\cdot} \\
+ @{method_def (HOL) metis} & : & \isarmeth \\
+ \end{matharray}
+
+ \begin{rail}
+ 'sledgehammer' (nameref *)
+ ;
+
+ 'metis' thmrefs
+ ;
+ \end{rail}
+
+ \begin{descr}
+
+ \item [@{command (HOL) sledgehammer}~@{text "prover\<^sub>1 \<dots>
+ prover\<^sub>n"}] invokes the specified automated theorem provers on
+ the first subgoal. Provers are run in parallel, the first
+ successful result is displayed, and the other attempts are
+ terminated.
+
+ Provers are defined in the theory context, see also @{command (HOL)
+ print_atps}. If no provers are given as arguments to @{command
+ (HOL) sledgehammer}, the system refers to the default defined as
+ ``ATP provers'' preference by the user interface.
+
+ There are additional preferences for timeout (default: 60 seconds),
+ and the maximum number of independent prover processes (default: 5);
+ excessive provers are automatically terminated.
+
+ \item [@{command (HOL) print_atps}] prints the list of automated
+ theorem provers available to the @{command (HOL) sledgehammer}
+ command.
+
+ \item [@{command (HOL) atp_info}] prints information about presently
+ running provers, including elapsed runtime, and the remaining time
+ until timeout.
+
+ \item [@{command (HOL) atp_kill}] terminates all presently running
+ provers.
+
+ \item [@{method (HOL) metis}~@{text "facts"}] invokes the Metis
+ prover with the given facts. Metis is an automated proof tool of
+ medium strength, but is fully integrated into Isabelle/HOL, with
+ explicit inferences going through the kernel. Thus its results are
+ guaranteed to be ``correct by construction''.
+
+ Note that all facts used with Metis need to be specified as explicit
+ arguments. There are no rule declarations as for other Isabelle
+ provers, like @{method blast} or @{method fast}.
+
+ \end{descr}
+*}
+
+
section {* Unstructured cases analysis and induction \label{sec:hol-induct-tac} *}
text {*