--- a/CookBook/Package/Ind_Examples.thy Sat Feb 14 16:09:04 2009 +0000
+++ b/CookBook/Package/Ind_Examples.thy Sun Feb 15 18:58:21 2009 +0000
@@ -5,8 +5,8 @@
section{* Examples of Inductive Definitions \label{sec:ind-examples} *}
text {*
- Let us first give three examples showing how to define by hand inductive
- predicates and then also how to prove by hand characteristic properties
+ Let us first give three examples showing how to define inductive
+ predicates by hand and then also how to prove by hand characteristic properties
about them, such as introduction rules and induction principles. From
these examples, we will figure out a general method for defining inductive
predicates. The aim in this section is \emph{not} to write proofs that are as
@@ -66,7 +66,7 @@
text {*
The proofs for the introduction are slightly more complicated. We need to prove
the facs @{prop "trcl R x x"} and @{prop "R x y \<Longrightarrow> trcl R y z \<Longrightarrow> trcl R x z"}.
- In order to prove the first goal, we again unfold the definition and
+ In order to prove the first fact, we again unfold the definition and
then apply the introdution rules for @{text "\<forall>"} and @{text "\<longrightarrow>"} as often as possible.
We then end up in the goal state:
*}
@@ -270,7 +270,7 @@
and the implication in the premise. We first convert the meta-level universal quantifier
and implication to their object-level counterparts. Unfolding the definition of
@{text accpart} and applying the introduction rules for @{text "\<forall>"} and @{text "\<longrightarrow>"}
- yields the following proof state:
+ yields the following goal state:
*}
(*<*)lemma accpartI: "(\<forall>y. R y x \<longrightarrow> accpart R y) \<Longrightarrow> accpart R x"
@@ -280,7 +280,7 @@
(*<*)oops(*>*)
text {*
- Applying the second assumption produces a proof state with the new local assumption
+ Applying the second assumption produces a goal state with the new local assumption
@{term "R y x"}, which will then be used to solve the goal @{term "P y"} using the
first assumption.
*}