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<head><title>subsets(ZZ,ZZ) -- produce all the subsets</title>
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<div><h1>subsets(ZZ,ZZ) -- produce all the subsets</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>subsets(n,j)</tt></div>
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<li><span>Function: <a href="_subsets.html" title="produce all the subsets">subsets</a></span></li>
<li><div class="single">Inputs:<ul><li><span><tt>n</tt>, <span>an <a href="___Z__Z.html">integer</a></span></span></li>
<li><span><tt>j</tt>, <span>an <a href="___Z__Z.html">integer</a></span></span></li>
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<li><div class="single">Outputs:<ul><li><span><span>a <a href="___List.html">list</a></span>, a list of the subsets of <tt>{0, ..., n-1}</tt> that have <tt>j</tt> elements; each subset is provided as a list</span></li>
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<div class="single"><h2>Description</h2>
<div><table class="examples"><tr><td><pre>i1 : subsets(7,3)
o1 = {{0, 1, 2}, {0, 1, 3}, {0, 2, 3}, {1, 2, 3}, {0, 1, 4}, {0, 2, 4}, {1,
------------------------------------------------------------------------
2, 4}, {0, 3, 4}, {1, 3, 4}, {2, 3, 4}, {0, 1, 5}, {0, 2, 5}, {1, 2, 5},
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{0, 3, 5}, {1, 3, 5}, {2, 3, 5}, {0, 4, 5}, {1, 4, 5}, {2, 4, 5}, {3, 4,
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5}, {0, 1, 6}, {0, 2, 6}, {1, 2, 6}, {0, 3, 6}, {1, 3, 6}, {2, 3, 6},
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{0, 4, 6}, {1, 4, 6}, {2, 4, 6}, {3, 4, 6}, {0, 5, 6}, {1, 5, 6}, {2, 5,
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6}, {3, 5, 6}, {4, 5, 6}}
o1 : List</pre>
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If each of the sets is reversed, then the resulting list is in lexicographic order.<table class="examples"><tr><td><pre>i2 : x = reverse \ subsets(6,3)
o2 = {{2, 1, 0}, {3, 1, 0}, {3, 2, 0}, {3, 2, 1}, {4, 1, 0}, {4, 2, 0}, {4,
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2, 1}, {4, 3, 0}, {4, 3, 1}, {4, 3, 2}, {5, 1, 0}, {5, 2, 0}, {5, 2, 1},
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{5, 3, 0}, {5, 3, 1}, {5, 3, 2}, {5, 4, 0}, {5, 4, 1}, {5, 4, 2}, {5, 4,
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3}}
o2 : List</pre>
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<tr><td><pre>i3 : sort x === x
o3 = true</pre>
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