Tutorial/Tutorial4.thy
changeset 3132 87eca760dcba
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3131:3e37322465e2 3132:87eca760dcba
    47 qed 
    47 qed 
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    50 text {*
    50 text {*
    51   In order to help establishing the property that the machine
    51   In order to help establishing the property that the machine
    52   calculates a normal form that corresponds to the evaluation 
    52   calculates a nomrmalform that corresponds to the evaluation 
    53   relation, we introduce the call-by-value small-step semantics.
    53   relation, we introduce the call-by-value small-step semantics.
    54 *}
    54 *}
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    57 equivariance val
    57 equivariance val
   122 
   122 
   123 section {* EXERCISE 13 *} 
   123 section {* EXERCISE 13 *} 
   124  
   124  
   125 text {*
   125 text {*
   126   The point of the cbv-reduction was that we can easily relatively 
   126   The point of the cbv-reduction was that we can easily relatively 
   127   establish the following property:
   127   establish the follwoing property:
   128 *}
   128 *}
   129 
   129 
   130 lemma machine_implies_cbvs_ctx:
   130 lemma machine_implies_cbvs_ctx:
   131   assumes a: "<e, Es> \<mapsto> <e', Es'>"
   131   assumes a: "<e, Es> \<mapsto> <e', Es'>"
   132   shows "(Es\<down>)\<lbrakk>e\<rbrakk> \<longrightarrow>cbv* (Es'\<down>)\<lbrakk>e'\<rbrakk>"
   132   shows "(Es\<down>)\<lbrakk>e\<rbrakk> \<longrightarrow>cbv* (Es'\<down>)\<lbrakk>e'\<rbrakk>"