Length minimizing graphs between a finite set of points

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Consider a set of $n$ points in the plane. Among all the connected graphs (trees) $T$ in the plane that have these $n$ points among their vertices, I am looking to find one such that the sum of its edge lengths is minimum. Note that this question is different from Minimum Spanning Tree as we allow $T$ to have vertices other than the given $n$ points. For example, if $n=3$, there are 2 possibilities: Let $A,B,C$ be the three given points. If one of the angles in the triangle $ABC$, say $ABC$ is bigger than $120^circ$ then AB+BC is the minimizing tree. If all the angles are less than $120^circ$, let $P$ be the point within the triangle $ABC$ such that the angles $APB$, $BPC$, $CPA$ are all $120^circ$. Then the tree $T$ with the set of vertices $A,B,C,P$ and edges $AP,BP,CP$ is the length minimizing one.



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    Consider a set of $n$ points in the plane. Among all the connected graphs (trees) $T$ in the plane that have these $n$ points among their vertices, I am looking to find one such that the sum of its edge lengths is minimum. Note that this question is different from Minimum Spanning Tree as we allow $T$ to have vertices other than the given $n$ points. For example, if $n=3$, there are 2 possibilities: Let $A,B,C$ be the three given points. If one of the angles in the triangle $ABC$, say $ABC$ is bigger than $120^circ$ then AB+BC is the minimizing tree. If all the angles are less than $120^circ$, let $P$ be the point within the triangle $ABC$ such that the angles $APB$, $BPC$, $CPA$ are all $120^circ$. Then the tree $T$ with the set of vertices $A,B,C,P$ and edges $AP,BP,CP$ is the length minimizing one.



    Is this problem worked out before?










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      Consider a set of $n$ points in the plane. Among all the connected graphs (trees) $T$ in the plane that have these $n$ points among their vertices, I am looking to find one such that the sum of its edge lengths is minimum. Note that this question is different from Minimum Spanning Tree as we allow $T$ to have vertices other than the given $n$ points. For example, if $n=3$, there are 2 possibilities: Let $A,B,C$ be the three given points. If one of the angles in the triangle $ABC$, say $ABC$ is bigger than $120^circ$ then AB+BC is the minimizing tree. If all the angles are less than $120^circ$, let $P$ be the point within the triangle $ABC$ such that the angles $APB$, $BPC$, $CPA$ are all $120^circ$. Then the tree $T$ with the set of vertices $A,B,C,P$ and edges $AP,BP,CP$ is the length minimizing one.



      Is this problem worked out before?










      share|cite|improve this question













      Consider a set of $n$ points in the plane. Among all the connected graphs (trees) $T$ in the plane that have these $n$ points among their vertices, I am looking to find one such that the sum of its edge lengths is minimum. Note that this question is different from Minimum Spanning Tree as we allow $T$ to have vertices other than the given $n$ points. For example, if $n=3$, there are 2 possibilities: Let $A,B,C$ be the three given points. If one of the angles in the triangle $ABC$, say $ABC$ is bigger than $120^circ$ then AB+BC is the minimizing tree. If all the angles are less than $120^circ$, let $P$ be the point within the triangle $ABC$ such that the angles $APB$, $BPC$, $CPA$ are all $120^circ$. Then the tree $T$ with the set of vertices $A,B,C,P$ and edges $AP,BP,CP$ is the length minimizing one.



      Is this problem worked out before?







      co.combinatorics graph-theory extremal-graph-theory






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      asked 3 hours ago









      Mohammad F. Tehrani

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          This is the so-called Steiner Tree Problem.






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            1 Answer
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            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

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            active

            oldest

            votes








            up vote
            4
            down vote



            accepted










            This is the so-called Steiner Tree Problem.






            share|cite|improve this answer
























              up vote
              4
              down vote



              accepted










              This is the so-called Steiner Tree Problem.






              share|cite|improve this answer






















                up vote
                4
                down vote



                accepted







                up vote
                4
                down vote



                accepted






                This is the so-called Steiner Tree Problem.






                share|cite|improve this answer












                This is the so-called Steiner Tree Problem.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered 2 hours ago









                Igor Rivin

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