Abstract characterization of polygonizations - MathOverflow most recent 30 from http://mathoverflow.net2013-05-24T05:16:56Zhttp://mathoverflow.net/feeds/question/114911http://www.creativecommons.org/licenses/by-nc/2.5/rdfhttp://mathoverflow.net/questions/114911/abstract-characterization-of-polygonizationsAbstract characterization of polygonizationsHans Stricker2012-11-29T18:44:42Z2012-11-30T08:57:39Z
<p>Consider a <a href="http://en.wikipedia.org/wiki/Triangulation_%2528geometry%2529" rel="nofollow">polygonization</a> of the plane by convex polygons of a given minimal size that meet edge-to-edge and vertex-to-vertex.</p>
<p><img src="http://i.stack.imgur.com/cYI09.png" alt="enter image description here">
<em><sup>What's the “official” name of such a polygonization?</sup></em></p>
<p>Such polygonizations of the plane induce infinite graphs.</p>
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<p>How can such abstract graphs be characterized?</p>
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<p>Somehow like this: “A graph is induced by a polygonization of the plane iff it is infinite, planar, 3-vertex-connected, and <em>P</em>.” (The question asks for property <em>P</em>, since infinite, planar and 3-vertex-connected those graphs obviously are.)</p>
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<p>Is it true, that the graphs that are
induced by a polygonization of the
<em>sphere</em> are exactly the <a href="http://en.wikipedia.org/wiki/Polyhedral_graph" rel="nofollow">polyhedral
graphs</a> which in turn are exactly the finite planar <a href="http://en.wikipedia.org/wiki/Steinitz%27s_theorem" rel="nofollow">3-vertex-connected graphs</a>?</p>
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<p>Finally I want to know:</p>
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<p>Can the graphs be characterized that are induced by a polygonization of <em>any</em> surface?</p>
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<p><sup>For the record: I asked this question at <a href="http://math.stackexchange.com/questions/246929/graphs-that-polygonize-a-manifold" rel="nofollow">MSE</a> before but it didn't earn a lot of interest.</sup></p>
http://mathoverflow.net/questions/114911/abstract-characterization-of-polygonizations/114935#114935Answer by Chad Brewbaker for Abstract characterization of polygonizationsChad Brewbaker2012-11-29T22:13:28Z2012-11-29T22:13:28Z<p>Voronoi digram/tessellation. <a href="http://en.wikipedia.org/wiki/Voronoi_diagram" rel="nofollow">http://en.wikipedia.org/wiki/Voronoi_diagram</a> </p>
http://mathoverflow.net/questions/114911/abstract-characterization-of-polygonizations/114947#114947Answer by Igor Rivin for Abstract characterization of polygonizationsIgor Rivin2012-11-30T01:16:01Z2012-11-30T01:16:01Z<p>For the OP's claim re *infinite*polyhedral graphs, the answer is yes, this is true, and a proof is in my paper:</p>
<p>Rivin, Igor. "Combinatorial optimization in geometry." Advances in Applied Mathematics 31.1 (2003): 242-271.</p>
<p>Basically, you can construct a circle packing with any prescribed (three-connected) combinatorics. What you lose when you go from finite to infinite is uniqueness, in a spectacular way: it should be true that one can get the carrier of the packing to be <em>any</em> Jordan domain.</p>