matita/matita/help/C/tac_case.html

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   2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>case</title><link rel="stylesheet" type="text/css" href="docbook.css" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="home" href="index.html" title="Matita V0.99.5 User Manual (rev. 0.99.5 )" /><link rel="up" href="sec_declarative_tactics.html" title="Chapter 8. Declarative Tactics" /><link rel="prev" href="tac_weproceedbycases.html" title="we proceed by cases on" /><link rel="next" href="tac_byinduction.html" title="by induction hypothesis we know" /></head><body><a xmlns="" href="../../../"><div class="matita_logo"><img src="figures/matita.png" alt="Tiny Matita logo" /><span>Matita Home</span></div></a><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">case</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="tac_weproceedbycases.html">Prev</a> </td><th width="60%" align="center">Chapter 8. Declarative Tactics</th><td width="20%" align="right"> <a accesskey="n" href="tac_byinduction.html">Next</a></td></tr></table><hr /></div><div class="sect1"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="tac_case"></a>case</h2></div></div></div><p><strong class="userinput"><code>case id (id1:T1) … (idn:Tn)</code></strong></p><p>
   3        </p><div class="variablelist"><dl class="variablelist"><dt><span class="term">Synopsis:</span></dt><dd><p><span class="bold"><strong>case</strong></span> <span class="emphasis"><em><a class="link" href="sec_terms.html#grammar.id">id</a></em></span> [<span class="bold"><strong>(</strong></span> <span class="emphasis"><em><a class="link" href="sec_terms.html#grammar.id">id</a></em></span> <span class="bold"><strong>:</strong></span> <span class="emphasis"><em><a class="link" href="sec_terms.html#grammar.term">term</a></em></span>  <span class="bold"><strong>)</strong></span>] … [<span class="bold"><strong>(</strong></span> <span class="emphasis"><em><a class="link" href="sec_terms.html#grammar.id">id</a></em></span> <span class="bold"><strong>:</strong></span> <span class="emphasis"><em><a class="link" href="sec_terms.html#grammar.term">term</a></em></span>  <span class="bold"><strong>)</strong></span>]</p></dd><dt><span class="term">Pre-condition:</span></dt><dd><p>The user must have started a proof by induction/cases that has not been concluded yet, <span class="command"><strong>id</strong></span> must be a constructor for the inductive type of the term under induction/case-analysis, and the case must not have already been proved.</p></dd><dt><span class="term">Action:</span></dt><dd><p>It starts the proof for the case <span class="command"><strong>id</strong></span>, where <span class="command"><strong>id1:T1</strong></span>,…,<span class="command"><strong>idn:Tn</strong></span> are the arguments of the constructor, each declared with its type.</p></dd><dt><span class="term">New sequents to prove:</span></dt><dd><p>The sequent for the case <span class="command"><strong>id</strong></span>.</p></dd></dl></div><p>
   4      </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="tac_weproceedbycases.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sec_declarative_tactics.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="tac_byinduction.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">we proceed by cases on </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> by induction hypothesis we know</td></tr></table></div></body></html>