src/HOL/Option.ML
author wenzelm
Wed, 15 Oct 1997 15:12:59 +0200
changeset 3872 a5839ecee7b8
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child 4032 4b1c69d8b767
permissions -rw-r--r--
tuned; prepare ext;
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(*  Title:      Option.ML
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    ID:         $Id$
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    Author:     Tobias Nipkow
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    Copyright   1996  TU Muenchen
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Derived rules
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*)
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open Option;
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goal Option.thy "P(case opt of None => a | Some(x) => b x) = \
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\                ((opt = None --> P a) & (!x. opt = Some x --> P(b x)))";
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by (option.induct_tac "opt" 1);
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by (Simp_tac 1);
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by (Asm_full_simp_tac 1);
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qed "expand_option_case";