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<head><title>isEmpty -- checks if a Polyhedron is empty</title>
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<div><h1>isEmpty -- checks if a Polyhedron is empty</h1>
<div class="single"><h2>Synopsis</h2>
<ul><li><div class="list"><dl class="element"><dt class="heading">Usage: </dt><dd class="value"><div><tt> b = isEmpty P</tt></div>
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<li><div class="single">Inputs:<ul><li><span><tt>P</tt>, <span>a <a href="___Polyhedron.html">convex polyhedron</a></span></span></li>
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<li><div class="single">Outputs:<ul><li><span><tt>b</tt>, <span>a <a href="../../Macaulay2Doc/html/___Boolean.html">Boolean value</a></span>, <a href="../../Macaulay2Doc/html/_true.html" title="">true</a> if the <a href="___Polyhedron.html" title="the class of all convex polyhedra">Polyhedron</a> is empty, <a href="../../Macaulay2Doc/html/_false.html" title="">false</a> otherwise</span></li>
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<div class="single"><h2>Description</h2>
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The polyhedron is empty if the dimension is -1.<table class="examples"><tr><td><pre>i1 : P = intersection(matrix{{1,0},{0,1},{-1,-1}},matrix{{-1},{1},{-1}})
o1 = {ambient dimension => 2 }
dimension of lineality space => 0
dimension of polyhedron => -1
number of facets => 0
number of rays => 0
number of vertices => 0
o1 : Polyhedron</pre>
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<tr><td><pre>i2 : isEmpty P
o2 = true</pre>
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<div class="waystouse"><h2>Ways to use <tt>isEmpty</tt> :</h2>
<ul><li>isEmpty(Polyhedron)</li>
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