doc-src/TutorialI/Advanced/simp.thy
changeset 13191 05a9929ee10e
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    14 
    14 
    15 subsubsection{*Congruence Rules*}
    15 subsubsection{*Congruence Rules*}
    16 
    16 
    17 text{*\label{sec:simp-cong}
    17 text{*\label{sec:simp-cong}
    18 While simplifying the conclusion $Q$
    18 While simplifying the conclusion $Q$
    19 of $P \Imp Q$, it is legal use the assumption $P$.
    19 of $P \Imp Q$, it is legal to use the assumption $P$.
    20 For $\Imp$ this policy is hardwired, but 
    20 For $\Imp$ this policy is hardwired, but 
    21 contextual information can also be made available for other
    21 contextual information can also be made available for other
    22 operators. For example, @{prop"xs = [] --> xs@xs = xs"} simplifies to @{term
    22 operators. For example, @{prop"xs = [] --> xs@xs = xs"} simplifies to @{term
    23 True} because we may use @{prop"xs = []"} when simplifying @{prop"xs@xs =
    23 True} because we may use @{prop"xs = []"} when simplifying @{prop"xs@xs =
    24 xs"}. The generation of contextual information during simplification is
    24 xs"}. The generation of contextual information during simplification is