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<head><title>iszero -- Tests whether something is zero.</title>
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<div><h1>iszero -- Tests whether something is zero.</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>iszero(c)</tt></div>
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<li><div class="single">Inputs:<ul><li><span><tt>c</tt>, <span>a <a href="../../Macaulay2Doc/html/___Thing.html">thing</a></span></span></li>
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<li><div class="single">Outputs:<ul><li><span><span>a <a href="../../Macaulay2Doc/html/___Boolean.html">Boolean value</a></span></span></li>
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<div class="single"><h2>Description</h2>
<div><p>Makes the test c == 0_<a href="../../Macaulay2Doc/html/_class.html" title="class of an object">class</a> c. Why does <a href="../../Macaulay2Doc/html/_zero.html" title="whether something is zero">zero</a> not work for elements in the cokernel of a matrix?</p>
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<table class="examples"><tr><td><pre>i1 : A= matrix {{-1, -1, -1}, {1, 0, 0}, {0, 1, 0}, {0, 0, 1}}
o1 = | -1 -1 -1 |
| 1 0 0 |
| 0 1 0 |
| 0 0 1 |
4 3
o1 : Matrix ZZ <--- ZZ</pre>
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<tr><td><pre>i2 : c1=cokerElement(vector {1,1,0,0},A)
o2 = | 2 |
| 0 |
| 0 |
| 0 |
o2 : cokernel | -1 -1 -1 |
| 1 0 0 |
| 0 1 0 |
| 0 0 1 |</pre>
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<tr><td><pre>i3 : c2=cokerElement(vector {1,-1,0,0},A)
o3 = 0
o3 : cokernel | -1 -1 -1 |
| 1 0 0 |
| 0 1 0 |
| 0 0 1 |</pre>
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<tr><td><pre>i4 : c2==(0_(class c2))
o4 = true</pre>
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<tr><td><pre>i5 : iszero c2
o5 = true</pre>
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<tr><td><pre>i6 : iszero c1
o6 = false</pre>
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<div class="single"><h2>See also</h2>
<ul><li><span><a href="../../Macaulay2Doc/html/_zero.html" title="whether something is zero">zero</a> -- whether something is zero</span></li>
<li><span><a href="_coker__Element.html" title="Gives an element in the cokernel of a matrix.">cokerElement</a> -- Gives an element in the cokernel of a matrix.</span></li>
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<div class="waystouse"><h2>Ways to use <tt>iszero</tt> :</h2>
<ul><li>iszero(Thing)</li>
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