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(* Title: HOL/ex/Acc.thy
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ID: $Id$
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Author: Lawrence C Paulson, Cambridge University Computer Laboratory
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Copyright 1994 University of Cambridge
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Inductive definition of acc(r)
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See Ch. Paulin-Mohring, Inductive Definitions in the System Coq.
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Research Report 92-49, LIP, ENS Lyon. Dec 1992.
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*)
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Acc = WF +
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consts
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pred :: "['b, ('a * 'b)set] => 'a set" (*Set of predecessors*)
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acc :: "('a * 'a)set => 'a set" (*Accessible part*)
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defs
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pred_def "pred(x,r) == {y. <y,x>:r}"
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inductive "acc(r)"
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intrs
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pred "pred(a,r): Pow(acc(r)) ==> a: acc(r)"
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monos "[Pow_mono]"
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end
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