2 theory find2 imports Main begin
6 txt{*\index{finding theorems}\index{searching theorems} In
7 \S\ref{sec:find}, we introduced Proof General's \pgmenu{Find} button
8 for finding theorems in the database via pattern matching. If we are
9 inside a proof, we can be more specific; we can search for introduction,
10 elimination and destruction rules \emph{with respect to the current goal}.
11 For this purpose, \pgmenu{Find} provides three aditional search criteria:
12 \texttt{intro}, \texttt{elim} and \texttt{dest}.
14 For example, given the goal @{subgoals[display,indent=0,margin=65]}
15 you can click on \pgmenu{Find} and type in the search expression
16 \texttt{intro}. You will be shown a few rules ending in @{text"\<Longrightarrow> ?P \<and> ?Q"},
17 among them @{thm[source]conjI}\@. You may even discover that
18 the very theorem you are trying to prove is already in the
19 database. Given the goal *}
22 lemma "A \<longrightarrow> A"
24 txt{*\vspace{-\bigskipamount}
25 @{subgoals[display,indent=0,margin=65]}
26 the search for \texttt{intro} finds not just @{thm[source] impI}
27 but also @{thm[source] imp_refl}: @{thm imp_refl}.
29 As before, search criteria can be combined freely: for example,
33 searches for all introduction rules that match the current goal and
34 mention the @{text"@"} function.
36 Searching for elimination and destruction rules via \texttt{elim} and
37 \texttt{dest} is analogous to \texttt{intro} but takes the assumptions