src/HOL/Recdef.thy
changeset 39302 d7728f65b353
parent 39198 f967a16dfcdd
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39301:e1bd8a54c40f 39302:d7728f65b353
    43 subsection{*Well-Founded Recursion*}
    43 subsection{*Well-Founded Recursion*}
    44 
    44 
    45 text{*cut*}
    45 text{*cut*}
    46 
    46 
    47 lemma cuts_eq: "(cut f r x = cut g r x) = (ALL y. (y,x):r --> f(y)=g(y))"
    47 lemma cuts_eq: "(cut f r x = cut g r x) = (ALL y. (y,x):r --> f(y)=g(y))"
    48 by (simp add: ext_iff cut_def)
    48 by (simp add: fun_eq_iff cut_def)
    49 
    49 
    50 lemma cut_apply: "(x,a):r ==> (cut f r a)(x) = f(x)"
    50 lemma cut_apply: "(x,a):r ==> (cut f r a)(x) = f(x)"
    51 by (simp add: cut_def)
    51 by (simp add: cut_def)
    52 
    52 
    53 text{*Inductive characterization of wfrec combinator; for details see:
    53 text{*Inductive characterization of wfrec combinator; for details see: