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<head><title>isIdeal -- whether something is an ideal</title>
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<div><h1>isIdeal -- whether something is an ideal</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>isIdeal I</tt></div>
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<li><div class="single">Inputs:<ul><li><span><tt>I</tt>, <span>a <a href="___Thing.html">thing</a></span></span></li>
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<li><div class="single">Outputs:<ul><li><span><span>a <a href="___Boolean.html">Boolean value</a></span>, <a href="_true.html" title="">true</a> if <tt>I</tt> is either an <a href="___Ideal.html">ideal</a>, a <a href="___Monomial__Ideal.html">monomial ideal</a> or a <a href="___Module.html">module</a> which is a submodule of a free module of rank 1 with generators in degree 0 and <a href="_false.html" title="">false</a> otherwise</span></li>
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<div class="single"><h2>Description</h2>
<div><table class="examples"><tr><td><pre>i1 : S = QQ[x,y,z];</pre>
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<tr><td><pre>i2 : I = ideal(x^2, y^2)
2 2
o2 = ideal (x , y )
o2 : Ideal of S</pre>
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<tr><td><pre>i3 : isIdeal I
o3 = true</pre>
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<tr><td><pre>i4 : J = monomialIdeal I
2 2
o4 = monomialIdeal (x , y )
o4 : MonomialIdeal of S</pre>
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<tr><td><pre>i5 : isIdeal J
o5 = true</pre>
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<tr><td><pre>i6 : R = QQ[a..d]/(a*b*c*d);</pre>
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<tr><td><pre>i7 : I = ideal(a^2,b^2) * R^1
o7 = image | a2 b2 |
1
o7 : R-module, submodule of R</pre>
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<tr><td><pre>i8 : isIdeal I
o8 = true</pre>
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<tr><td><pre>i9 : J = a^2 * R^2 + a*b * R^2
o9 = image | a2 0 ab 0 |
| 0 a2 0 ab |
2
o9 : R-module, submodule of R</pre>
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<tr><td><pre>i10 : isIdeal J
o10 = false</pre>
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<div class="single"><h2>See also</h2>
<ul><li><span><a href="_ideal_lp__Module_rp.html" title="converts a module to an ideal">ideal(Module)</a> -- converts a module to an ideal</span></li>
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<div class="waystouse"><h2>Ways to use <tt>isIdeal</tt> :</h2>
<ul><li>isIdeal(Ideal)</li>
<li>isIdeal(Module)</li>
<li>isIdeal(MonomialIdeal)</li>
<li>isIdeal(Thing)</li>
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