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<p style="line-height: 200%" align="center"><b><font size="5">谓词公式中的范式</font></b> </p>
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前束范式</b></li>
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<p style="line-height: 200%"> 在谓词公式中，若所有量词的前面均不出现<a href="content-2-1-2.htm#content-2-1-2-weicibianyuan">谓词变元</a>和<a href="content-1-1-2.htm#content-1-1-2-lianjieci">联结词</a>，则该谓词公式称为一个前束范式。<br>
例如：<img src="image/renyi.gif" width="9" height="11">x<img src="image/cunzai.gif" width="7" height="11" >y<img src="image/cunzai.gif" width="7" height="11" >z(A(x)<img src="image/xiqu.gif" width="9" height="15">B(y,z)<img src="image/hequ.gif" width="9" height="11">C(z))是一个前束范式，而<img src="image/renyi.gif" width="9" height="11">xA(x)<img src="image/cunzai.gif" width="7" height="11" >y<img src="image/cunzai.gif" width="7" height="11" >z(B(y,z)C(z))不是前束范式。</p>
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母式</b></li>
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<p style="line-height: 200%"> 前束范式中位于所有量词后面的部分称为该前束范式的母式。<br>
例如在上面的前束范式中， A(x)<img src="image/xiqu.gif" width="9" height="15">B(y,z)<img src="image/hequ.gif" width="9" height="11">C(z)
部分为该前束范式的母式。<br>
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<p style="line-height: 200%"><b>前束合取范式</b></li>
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<p style="line-height: 200%"> 在谓词公式的前束范式中，若母式为合取式，则称此前束范式为前束合取范式。<br>
例如前束范式： <img src="image/renyi.gif" width="9" height="11">x<img src="image/cunzai.gif" width="7" height="11" >y<img src="image/cunzai.gif" width="7" height="11" >z(B(x,y,z)<img src="image/hequ.gif" width="9" height="11">C(z))
为前束合取范式，而前束范式 ： <img src="image/renyi.gif" width="9" height="11">x<img src="image/cunzai.gif" width="7" height="11" >y<img src="image/cunzai.gif" width="7" height="11" >z(A(x)<img src="image/xiqu.gif" width="9" height="15">B(y,z)<img src="image/hequ.gif" width="9" height="11">C(z))
就不是。 <br>
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<p style="line-height: 200%"><b>前束析取范式</b></p>
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<p style="line-height: 200%"> 在谓词公式的前束范式中，若母式为析取式，则称此前束范式为前束析取范式。 <br>
例如前束范式： <img src="image/renyi.gif" width="9" height="11">x<img src="image/cunzai.gif" width="7" height="11" >y<img src="image/cunzai.gif" width="7" height="11" >z(B(x,y,z)<img src="image/xiqu.gif" width="9" height="15">C(z))
为 前束合取范式，而前束范式 ： <img src="image/renyi.gif" width="9" height="11">x<img src="image/cunzai.gif" width="7" height="11" >y<img src="image/cunzai.gif" width="7" height="11" >z(A(x)<img src="image/xiqu.gif" width="9" height="15">B(y,z)<img src="image/hequ.gif" width="9" height="11">C(z))
就不是。</p>
<p style="line-height: 200%"><b>例:求公式的前束范式</b> </p>
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<p style="line-height: 150%"><img src="image/renyi.gif" width="9" height="11">xF(x)<img src="image/hequ.gif" width="9" height="11"><img src="image/fei.gif" width="10" height="5"><img src="image/cunzai.gif" width="7" height="11">xG(x)</p>
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<p style="line-height: 150%"><img src="image/renyi.gif" width="9" height="11">xF(x)<img src="image/xiqu.gif" width="9" height="15"><img src="image/fei.gif" width="10" height="5"><img src="image/cunzai.gif" width="7" height="11">xG(x)</p>
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<p style="line-height: 150%"><img src="image/renyi.gif" width="9" height="11">xF(x)<img src="image/hequ.gif" width="9" height="11"><img src="image/cunzai.gif" width="7" height="11">xG(x)</p>
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<p style="line-height: 150%"><img src="image/renyi.gif" width="9" height="11">xF(x)<img border="0" src="image/yunhan.gif" width="15" height="9"><img src="image/cunzai.gif" width="7" height="11">xG(x)</p>
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<p style="line-height: 150%"><img src="image/cunzai.gif" width="7" height="11">xF(x)<img border="0" src="image/yunhan.gif" width="15" height="9"><img src="image/renyi.gif" width="9" height="11">xG(x)</p>
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<p style="line-height: 150%"><img src="image/renyi.gif" width="9" height="11">xF(x)<img border="0" src="image/yunhan.gif" width="15" height="9"><img src="image/cunzai.gif" width="7" height="11">yG(y)</p>
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<p style="line-height: 150%">(<img src="image/renyi.gif" width="9" height="11">xF(x,y)<img border="0" src="image/yunhan.gif" width="15" height="9"><img src="image/cunzai.gif" width="7" height="11">yG(y))<img border="0" src="image/yunhan.gif" width="15" height="9"><img src="image/renyi.gif" width="9" height="11">xH(x,y)</p>
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<p style="line-height: 150%">(<img src="image/renyi.gif" width="9" height="11">xF(x,y) <img src="image/xiqu.gif" width="9" height="15">
<img src="image/renyi.gif" width="9" height="11">yG(x,y))<img src="image/hequ.gif" width="9" height="11">
<img src="image/cunzai.gif" width="7" height="11">zH(x,y,z)</p>
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