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(* Title: CCL/hered.thy


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ID: $Id$


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Author: Martin Coen


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Copyright 1993 University of Cambridge


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Hereditary Termination  cf. Martin Lo\"f


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Note that this is based on an untyped equality and so lam x.b(x) is only


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hereditarily terminating if ALL x.b(x) is. Not so useful for functions!


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*)


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Hered = Type +


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consts


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(*** Predicates ***)


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HTTgen :: "i set => i set"


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HTT :: "i set"


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rules


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(*** Definitions of Hereditary Termination ***)


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HTTgen_def

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"HTTgen(R) == {t. t=true  t=false  (EX a b.t=<a,b> & a : R & b : R) 


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(EX f. t=lam x.f(x) & (ALL x.f(x) : R))}"

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HTT_def "HTT == gfp(HTTgen)"


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end
