3-polytope with 9 vertices and 8 facets












0












$begingroup$


enter image description here



My guess is that this is a 3-polytope, since the existence of the two facets {357} and {048} rules out the possibility of dimensionality 2 and 4.



How can I go about sketching it?










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    0












    $begingroup$


    enter image description here



    My guess is that this is a 3-polytope, since the existence of the two facets {357} and {048} rules out the possibility of dimensionality 2 and 4.



    How can I go about sketching it?










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      enter image description here



      My guess is that this is a 3-polytope, since the existence of the two facets {357} and {048} rules out the possibility of dimensionality 2 and 4.



      How can I go about sketching it?










      share|cite|improve this question









      $endgroup$




      enter image description here



      My guess is that this is a 3-polytope, since the existence of the two facets {357} and {048} rules out the possibility of dimensionality 2 and 4.



      How can I go about sketching it?







      polytopes discrete-geometry






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      asked Jan 30 at 12:17









      ensbanaensbana

      252214




      252214






















          3 Answers
          3






          active

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          1












          $begingroup$

          There are many ways of sketching it, but they all are quite similar. I started with the triangle ${3, 5, 7}$:



          enter image description here



          Then I looked at all facets (faces, really) which shared a side with this one. They are the ones in the top row. I filled them in to get this:



          enter image description here



          (Note that the top triangle isn't a face; it's "open".) Then I took the remaining three quadrilateral faces, put them on:



          enter image description here



          And thus the sketch was finished.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            So the vertices of a facet does not necessarily follow the order specified in the question? (e.g. {1567} should really be {1657} or {1756}?)
            $endgroup$
            – ensbana
            Jan 30 at 12:43






          • 1




            $begingroup$
            @ensbana The vertices for each face are listed in increasing order, with no actual geometrical significance, yes.
            $endgroup$
            – Arthur
            Jan 30 at 12:44





















          0












          $begingroup$

          Identify shared edges, and use that to draw a graph of the polytope connections.



          For instance, 3-5-7 and 1-2-3-7 have the shared edge 3-7. So, putting 3-5-7 in the center of your graph, you have 3 and 7 next to 1 and 2 in some order. Similarly 3 and 5 are next to 2 and 6, and 5 and 7 ate next to 1 and 6. This combibation is consistent with the graph having 3 directly connected to 2, 5 connected to 6, and 7 connected to 1. You also connect 1, 2 and 6 to each other to close the quadrilateral faces.



          Now you have the open edges 1-2, 1-6, and 2-6. Find the faces that share those edges and draw them in using similar logic to that above. Your complete graph now shows the two triangular faces (3-5-7 in the center and 0-4-8 in the exterior region) sandwiched around two layers of quadrilaterals. Can you see now what sort of polyhedron has layers of quadrilaterals capped by triangles at opposite ends?






          share|cite|improve this answer









          $endgroup$





















            0












            $begingroup$

            The sketch of @arthur already shows the shape.

            If you'd set up the 6 tetragons as trapezia, you'd recognize this figure to be a bitruncated triagular bipyramid.



            --- rk






            share|cite|improve this answer









            $endgroup$














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              3 Answers
              3






              active

              oldest

              votes








              3 Answers
              3






              active

              oldest

              votes









              active

              oldest

              votes






              active

              oldest

              votes









              1












              $begingroup$

              There are many ways of sketching it, but they all are quite similar. I started with the triangle ${3, 5, 7}$:



              enter image description here



              Then I looked at all facets (faces, really) which shared a side with this one. They are the ones in the top row. I filled them in to get this:



              enter image description here



              (Note that the top triangle isn't a face; it's "open".) Then I took the remaining three quadrilateral faces, put them on:



              enter image description here



              And thus the sketch was finished.






              share|cite|improve this answer









              $endgroup$













              • $begingroup$
                So the vertices of a facet does not necessarily follow the order specified in the question? (e.g. {1567} should really be {1657} or {1756}?)
                $endgroup$
                – ensbana
                Jan 30 at 12:43






              • 1




                $begingroup$
                @ensbana The vertices for each face are listed in increasing order, with no actual geometrical significance, yes.
                $endgroup$
                – Arthur
                Jan 30 at 12:44


















              1












              $begingroup$

              There are many ways of sketching it, but they all are quite similar. I started with the triangle ${3, 5, 7}$:



              enter image description here



              Then I looked at all facets (faces, really) which shared a side with this one. They are the ones in the top row. I filled them in to get this:



              enter image description here



              (Note that the top triangle isn't a face; it's "open".) Then I took the remaining three quadrilateral faces, put them on:



              enter image description here



              And thus the sketch was finished.






              share|cite|improve this answer









              $endgroup$













              • $begingroup$
                So the vertices of a facet does not necessarily follow the order specified in the question? (e.g. {1567} should really be {1657} or {1756}?)
                $endgroup$
                – ensbana
                Jan 30 at 12:43






              • 1




                $begingroup$
                @ensbana The vertices for each face are listed in increasing order, with no actual geometrical significance, yes.
                $endgroup$
                – Arthur
                Jan 30 at 12:44
















              1












              1








              1





              $begingroup$

              There are many ways of sketching it, but they all are quite similar. I started with the triangle ${3, 5, 7}$:



              enter image description here



              Then I looked at all facets (faces, really) which shared a side with this one. They are the ones in the top row. I filled them in to get this:



              enter image description here



              (Note that the top triangle isn't a face; it's "open".) Then I took the remaining three quadrilateral faces, put them on:



              enter image description here



              And thus the sketch was finished.






              share|cite|improve this answer









              $endgroup$



              There are many ways of sketching it, but they all are quite similar. I started with the triangle ${3, 5, 7}$:



              enter image description here



              Then I looked at all facets (faces, really) which shared a side with this one. They are the ones in the top row. I filled them in to get this:



              enter image description here



              (Note that the top triangle isn't a face; it's "open".) Then I took the remaining three quadrilateral faces, put them on:



              enter image description here



              And thus the sketch was finished.







              share|cite|improve this answer












              share|cite|improve this answer



              share|cite|improve this answer










              answered Jan 30 at 12:38









              ArthurArthur

              122k7122210




              122k7122210












              • $begingroup$
                So the vertices of a facet does not necessarily follow the order specified in the question? (e.g. {1567} should really be {1657} or {1756}?)
                $endgroup$
                – ensbana
                Jan 30 at 12:43






              • 1




                $begingroup$
                @ensbana The vertices for each face are listed in increasing order, with no actual geometrical significance, yes.
                $endgroup$
                – Arthur
                Jan 30 at 12:44




















              • $begingroup$
                So the vertices of a facet does not necessarily follow the order specified in the question? (e.g. {1567} should really be {1657} or {1756}?)
                $endgroup$
                – ensbana
                Jan 30 at 12:43






              • 1




                $begingroup$
                @ensbana The vertices for each face are listed in increasing order, with no actual geometrical significance, yes.
                $endgroup$
                – Arthur
                Jan 30 at 12:44


















              $begingroup$
              So the vertices of a facet does not necessarily follow the order specified in the question? (e.g. {1567} should really be {1657} or {1756}?)
              $endgroup$
              – ensbana
              Jan 30 at 12:43




              $begingroup$
              So the vertices of a facet does not necessarily follow the order specified in the question? (e.g. {1567} should really be {1657} or {1756}?)
              $endgroup$
              – ensbana
              Jan 30 at 12:43




              1




              1




              $begingroup$
              @ensbana The vertices for each face are listed in increasing order, with no actual geometrical significance, yes.
              $endgroup$
              – Arthur
              Jan 30 at 12:44






              $begingroup$
              @ensbana The vertices for each face are listed in increasing order, with no actual geometrical significance, yes.
              $endgroup$
              – Arthur
              Jan 30 at 12:44













              0












              $begingroup$

              Identify shared edges, and use that to draw a graph of the polytope connections.



              For instance, 3-5-7 and 1-2-3-7 have the shared edge 3-7. So, putting 3-5-7 in the center of your graph, you have 3 and 7 next to 1 and 2 in some order. Similarly 3 and 5 are next to 2 and 6, and 5 and 7 ate next to 1 and 6. This combibation is consistent with the graph having 3 directly connected to 2, 5 connected to 6, and 7 connected to 1. You also connect 1, 2 and 6 to each other to close the quadrilateral faces.



              Now you have the open edges 1-2, 1-6, and 2-6. Find the faces that share those edges and draw them in using similar logic to that above. Your complete graph now shows the two triangular faces (3-5-7 in the center and 0-4-8 in the exterior region) sandwiched around two layers of quadrilaterals. Can you see now what sort of polyhedron has layers of quadrilaterals capped by triangles at opposite ends?






              share|cite|improve this answer









              $endgroup$


















                0












                $begingroup$

                Identify shared edges, and use that to draw a graph of the polytope connections.



                For instance, 3-5-7 and 1-2-3-7 have the shared edge 3-7. So, putting 3-5-7 in the center of your graph, you have 3 and 7 next to 1 and 2 in some order. Similarly 3 and 5 are next to 2 and 6, and 5 and 7 ate next to 1 and 6. This combibation is consistent with the graph having 3 directly connected to 2, 5 connected to 6, and 7 connected to 1. You also connect 1, 2 and 6 to each other to close the quadrilateral faces.



                Now you have the open edges 1-2, 1-6, and 2-6. Find the faces that share those edges and draw them in using similar logic to that above. Your complete graph now shows the two triangular faces (3-5-7 in the center and 0-4-8 in the exterior region) sandwiched around two layers of quadrilaterals. Can you see now what sort of polyhedron has layers of quadrilaterals capped by triangles at opposite ends?






                share|cite|improve this answer









                $endgroup$
















                  0












                  0








                  0





                  $begingroup$

                  Identify shared edges, and use that to draw a graph of the polytope connections.



                  For instance, 3-5-7 and 1-2-3-7 have the shared edge 3-7. So, putting 3-5-7 in the center of your graph, you have 3 and 7 next to 1 and 2 in some order. Similarly 3 and 5 are next to 2 and 6, and 5 and 7 ate next to 1 and 6. This combibation is consistent with the graph having 3 directly connected to 2, 5 connected to 6, and 7 connected to 1. You also connect 1, 2 and 6 to each other to close the quadrilateral faces.



                  Now you have the open edges 1-2, 1-6, and 2-6. Find the faces that share those edges and draw them in using similar logic to that above. Your complete graph now shows the two triangular faces (3-5-7 in the center and 0-4-8 in the exterior region) sandwiched around two layers of quadrilaterals. Can you see now what sort of polyhedron has layers of quadrilaterals capped by triangles at opposite ends?






                  share|cite|improve this answer









                  $endgroup$



                  Identify shared edges, and use that to draw a graph of the polytope connections.



                  For instance, 3-5-7 and 1-2-3-7 have the shared edge 3-7. So, putting 3-5-7 in the center of your graph, you have 3 and 7 next to 1 and 2 in some order. Similarly 3 and 5 are next to 2 and 6, and 5 and 7 ate next to 1 and 6. This combibation is consistent with the graph having 3 directly connected to 2, 5 connected to 6, and 7 connected to 1. You also connect 1, 2 and 6 to each other to close the quadrilateral faces.



                  Now you have the open edges 1-2, 1-6, and 2-6. Find the faces that share those edges and draw them in using similar logic to that above. Your complete graph now shows the two triangular faces (3-5-7 in the center and 0-4-8 in the exterior region) sandwiched around two layers of quadrilaterals. Can you see now what sort of polyhedron has layers of quadrilaterals capped by triangles at opposite ends?







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered Jan 30 at 13:00









                  Oscar LanziOscar Lanzi

                  13.5k12136




                  13.5k12136























                      0












                      $begingroup$

                      The sketch of @arthur already shows the shape.

                      If you'd set up the 6 tetragons as trapezia, you'd recognize this figure to be a bitruncated triagular bipyramid.



                      --- rk






                      share|cite|improve this answer









                      $endgroup$


















                        0












                        $begingroup$

                        The sketch of @arthur already shows the shape.

                        If you'd set up the 6 tetragons as trapezia, you'd recognize this figure to be a bitruncated triagular bipyramid.



                        --- rk






                        share|cite|improve this answer









                        $endgroup$
















                          0












                          0








                          0





                          $begingroup$

                          The sketch of @arthur already shows the shape.

                          If you'd set up the 6 tetragons as trapezia, you'd recognize this figure to be a bitruncated triagular bipyramid.



                          --- rk






                          share|cite|improve this answer









                          $endgroup$



                          The sketch of @arthur already shows the shape.

                          If you'd set up the 6 tetragons as trapezia, you'd recognize this figure to be a bitruncated triagular bipyramid.



                          --- rk







                          share|cite|improve this answer












                          share|cite|improve this answer



                          share|cite|improve this answer










                          answered Jan 31 at 12:38









                          Dr. Richard KlitzingDr. Richard Klitzing

                          1,77026




                          1,77026






























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