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    <title>isSNC -- whether the divisor is simple normal crossings</title>
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o2 = Div(x, z) + -2*Div(y, z)

o2 : WeilDivisor on R</code></pre>
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              <pre><code class="language-macaulay2">i3 : isSNC( D )

o3 = false</code></pre>
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              <pre><code class="language-macaulay2">i4 : R = QQ[x, y];</code></pre>
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              <pre><code class="language-macaulay2">i5 : D = divisor(x*y*(x+y))

o5 = Div(x+y) + Div(y) + Div(x)

o5 : WeilDivisor on R</code></pre>
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              <pre><code class="language-macaulay2">i6 : isSNC( D )

o6 = false</code></pre>
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              <pre><code class="language-macaulay2">i7 : R = QQ[x, y];</code></pre>
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              <pre><code class="language-macaulay2">i8 : D = divisor(x*y*(x+1))

o8 = Div(y) + Div(x) + Div(x+1)

o8 : WeilDivisor on R</code></pre>
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              <pre><code class="language-macaulay2">i9 : isSNC( D )

o9 = true</code></pre>
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          <p>If <span class="tt">IsGraded</span> is set to <span class="tt">true</span> (default <span class="tt">false</span>), then the divisor is treated as if it is on the $Proj$ of the ambient ring.  In particular, non-SNC behavior at the origin is ignored.</p>
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              <pre><code class="language-macaulay2">i10 : R = QQ[x, y, z] / ideal(x * y - z^2 );</code></pre>
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              <pre><code class="language-macaulay2">i11 : D = divisor({1, -2}, {ideal(x, z), ideal(y, z)})

o11 = -2*Div(y, z) + Div(x, z)

o11 : WeilDivisor on R</code></pre>
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              <pre><code class="language-macaulay2">i12 : isSNC( D, IsGraded => true )

o12 = true</code></pre>
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              <pre><code class="language-macaulay2">i13 : R = QQ[x, y];</code></pre>
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              <pre><code class="language-macaulay2">i14 : D = divisor(x*y*(x+y))

o14 = Div(y) + Div(x) + Div(x+y)

o14 : WeilDivisor on R</code></pre>
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              <pre><code class="language-macaulay2">i15 : isSNC( D, IsGraded => true )

o15 = true</code></pre>
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              <pre><code class="language-macaulay2">i16 : R = QQ[x,y,z];</code></pre>
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              <pre><code class="language-macaulay2">i17 : D = divisor(x*y*(x+y))

o17 = Div(x) + Div(x+y) + Div(y)

o17 : WeilDivisor on R</code></pre>
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              <pre><code class="language-macaulay2">i18 : isSNC( D, IsGraded => true)

o18 = false</code></pre>
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          <p>The output value of this function is stored in the divisor's cache with the value of the last <span class="tt">IsGraded</span> option.  If you change the <span class="tt">IsGraded</span> option, the value will be recomputed.</p>
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          <h2>Ways to use <span class="tt">isSNC</span>:</h2>
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            <li><kbd>isSNC(BasicDivisor)</kbd></li>
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          <h2>For the programmer</h2>
          <p>The object <a title="whether the divisor is simple normal crossings" href="_is__S__N__C.html">isSNC</a> is <span>a <a title="a type of method function" href="../../Macaulay2Doc/html/___Method__Function__With__Options.html">method function with options</a></span>.</p>
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        <div class="waystouse">
          <p>The source of this document is in <span class="tt">Divisor.m2:4154:0</span>.</p>
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Edit File: _is__S__N__C.html

Edit File: _isSN__C.html