Volume of polyhedron












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Given the following polyhedron: All the $ntimes n$ matrices $boldsymbol{X}$ with elements $x_{ij}in(0,1)$ such that
$$boldsymbol{X}cdotboldsymbol{1}=boldsymbol{r}, boldsymbol{1}^Tboldsymbol{X}=boldsymbol{c}^T$$



For some given vectors $boldsymbol{r}$ and $boldsymbol{c}$.



Can I calculate the volume of this polyhedron? Can I calculate it's surface?










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    3












    $begingroup$


    Given the following polyhedron: All the $ntimes n$ matrices $boldsymbol{X}$ with elements $x_{ij}in(0,1)$ such that
    $$boldsymbol{X}cdotboldsymbol{1}=boldsymbol{r}, boldsymbol{1}^Tboldsymbol{X}=boldsymbol{c}^T$$



    For some given vectors $boldsymbol{r}$ and $boldsymbol{c}$.



    Can I calculate the volume of this polyhedron? Can I calculate it's surface?










    share|cite|improve this question









    $endgroup$















      3












      3








      3


      1



      $begingroup$


      Given the following polyhedron: All the $ntimes n$ matrices $boldsymbol{X}$ with elements $x_{ij}in(0,1)$ such that
      $$boldsymbol{X}cdotboldsymbol{1}=boldsymbol{r}, boldsymbol{1}^Tboldsymbol{X}=boldsymbol{c}^T$$



      For some given vectors $boldsymbol{r}$ and $boldsymbol{c}$.



      Can I calculate the volume of this polyhedron? Can I calculate it's surface?










      share|cite|improve this question









      $endgroup$




      Given the following polyhedron: All the $ntimes n$ matrices $boldsymbol{X}$ with elements $x_{ij}in(0,1)$ such that
      $$boldsymbol{X}cdotboldsymbol{1}=boldsymbol{r}, boldsymbol{1}^Tboldsymbol{X}=boldsymbol{c}^T$$



      For some given vectors $boldsymbol{r}$ and $boldsymbol{c}$.



      Can I calculate the volume of this polyhedron? Can I calculate it's surface?







      linear-algebra matrices






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      asked Jan 7 at 8:59









      MathGirl88MathGirl88

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          When $boldsymbol{r}=boldsymbol{c}=(1,1,dots,1)$ the polytope $X$ is the Birkhoff polytope of $ntimes n$ doubly-stochastic matrices. Computing its $(n-1)^2$-dimensional volume is a well-known difficult problem. An answer is given by De Loera, Liu, and Yoshida in http://arxiv.org/abs/math/0701866, but it is quite a complicated formula. For generalizing it to $boldsymbol{r}$ and $boldsymbol{c}$ and to higher dimension, see De Loera's survey at http://arxiv.org/pdf/1307.0124.pdf. For additional information in the case of the Birkhoff polytope, see OEIS A078524, A078525, A037302.






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            $begingroup$

            When $boldsymbol{r}=boldsymbol{c}=(1,1,dots,1)$ the polytope $X$ is the Birkhoff polytope of $ntimes n$ doubly-stochastic matrices. Computing its $(n-1)^2$-dimensional volume is a well-known difficult problem. An answer is given by De Loera, Liu, and Yoshida in http://arxiv.org/abs/math/0701866, but it is quite a complicated formula. For generalizing it to $boldsymbol{r}$ and $boldsymbol{c}$ and to higher dimension, see De Loera's survey at http://arxiv.org/pdf/1307.0124.pdf. For additional information in the case of the Birkhoff polytope, see OEIS A078524, A078525, A037302.






            share|cite|improve this answer









            $endgroup$


















              9












              $begingroup$

              When $boldsymbol{r}=boldsymbol{c}=(1,1,dots,1)$ the polytope $X$ is the Birkhoff polytope of $ntimes n$ doubly-stochastic matrices. Computing its $(n-1)^2$-dimensional volume is a well-known difficult problem. An answer is given by De Loera, Liu, and Yoshida in http://arxiv.org/abs/math/0701866, but it is quite a complicated formula. For generalizing it to $boldsymbol{r}$ and $boldsymbol{c}$ and to higher dimension, see De Loera's survey at http://arxiv.org/pdf/1307.0124.pdf. For additional information in the case of the Birkhoff polytope, see OEIS A078524, A078525, A037302.






              share|cite|improve this answer









              $endgroup$
















                9












                9








                9





                $begingroup$

                When $boldsymbol{r}=boldsymbol{c}=(1,1,dots,1)$ the polytope $X$ is the Birkhoff polytope of $ntimes n$ doubly-stochastic matrices. Computing its $(n-1)^2$-dimensional volume is a well-known difficult problem. An answer is given by De Loera, Liu, and Yoshida in http://arxiv.org/abs/math/0701866, but it is quite a complicated formula. For generalizing it to $boldsymbol{r}$ and $boldsymbol{c}$ and to higher dimension, see De Loera's survey at http://arxiv.org/pdf/1307.0124.pdf. For additional information in the case of the Birkhoff polytope, see OEIS A078524, A078525, A037302.






                share|cite|improve this answer









                $endgroup$



                When $boldsymbol{r}=boldsymbol{c}=(1,1,dots,1)$ the polytope $X$ is the Birkhoff polytope of $ntimes n$ doubly-stochastic matrices. Computing its $(n-1)^2$-dimensional volume is a well-known difficult problem. An answer is given by De Loera, Liu, and Yoshida in http://arxiv.org/abs/math/0701866, but it is quite a complicated formula. For generalizing it to $boldsymbol{r}$ and $boldsymbol{c}$ and to higher dimension, see De Loera's survey at http://arxiv.org/pdf/1307.0124.pdf. For additional information in the case of the Birkhoff polytope, see OEIS A078524, A078525, A037302.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Jan 7 at 14:39









                Richard StanleyRichard Stanley

                28.5k8113186




                28.5k8113186






























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