Are there $3$ disjoint copies of $2K_{3,3} cup (K_{5,5} setminus C_{10})$ in $K_{11,11}$?












7












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Question: Are there $3$ edge disjoint copies of $H:=2K_{3,3} cup (K_{5,5} setminus C_{10})$ in $K_{11,11}$?



Here's a drawing of $H$:



$2K_{3,3} cup (K_{5,5} setminus C_{10})$



I'm working on a Latin squares research problem and trying to get a construction to work. If it would work, it would give a solution to this problem. Only, I can't get it to work easily. Maybe the above doesn't exist, and my construction won't work in this case.




  • We see $H$ is regular with degree $3$, and the degrees of vertices in $K_{11,11}$ is $11$, so no clash there.

  • $H$ has $33$ edges while $K_{11,11}$ has $121$ edges, so no clash there.










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    7












    $begingroup$


    Question: Are there $3$ edge disjoint copies of $H:=2K_{3,3} cup (K_{5,5} setminus C_{10})$ in $K_{11,11}$?



    Here's a drawing of $H$:



    $2K_{3,3} cup (K_{5,5} setminus C_{10})$



    I'm working on a Latin squares research problem and trying to get a construction to work. If it would work, it would give a solution to this problem. Only, I can't get it to work easily. Maybe the above doesn't exist, and my construction won't work in this case.




    • We see $H$ is regular with degree $3$, and the degrees of vertices in $K_{11,11}$ is $11$, so no clash there.

    • $H$ has $33$ edges while $K_{11,11}$ has $121$ edges, so no clash there.










    share|cite|improve this question











    $endgroup$















      7












      7








      7


      3



      $begingroup$


      Question: Are there $3$ edge disjoint copies of $H:=2K_{3,3} cup (K_{5,5} setminus C_{10})$ in $K_{11,11}$?



      Here's a drawing of $H$:



      $2K_{3,3} cup (K_{5,5} setminus C_{10})$



      I'm working on a Latin squares research problem and trying to get a construction to work. If it would work, it would give a solution to this problem. Only, I can't get it to work easily. Maybe the above doesn't exist, and my construction won't work in this case.




      • We see $H$ is regular with degree $3$, and the degrees of vertices in $K_{11,11}$ is $11$, so no clash there.

      • $H$ has $33$ edges while $K_{11,11}$ has $121$ edges, so no clash there.










      share|cite|improve this question











      $endgroup$




      Question: Are there $3$ edge disjoint copies of $H:=2K_{3,3} cup (K_{5,5} setminus C_{10})$ in $K_{11,11}$?



      Here's a drawing of $H$:



      $2K_{3,3} cup (K_{5,5} setminus C_{10})$



      I'm working on a Latin squares research problem and trying to get a construction to work. If it would work, it would give a solution to this problem. Only, I can't get it to work easily. Maybe the above doesn't exist, and my construction won't work in this case.




      • We see $H$ is regular with degree $3$, and the degrees of vertices in $K_{11,11}$ is $11$, so no clash there.

      • $H$ has $33$ edges while $K_{11,11}$ has $121$ edges, so no clash there.







      graph-theory






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      edited Jan 13 '17 at 14:25









      Ethan Bolker

      42.7k549113




      42.7k549113










      asked Jan 13 '17 at 14:21









      Rebecca J. StonesRebecca J. Stones

      20.9k22781




      20.9k22781






















          1 Answer
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          3












          $begingroup$

          Since I solved the other linked problem, I figured I might as well give simulated annealing a go on this one.



          The answer is also yes; in fact, here, we can find $3$ disjoint copies of $2K_{3,3} cup (K_{5,5} - P_{10})$. I added the extra edge in an attempt to make the problem a bit more constrained so that the solution would come out nicer, but I'm not sure how much of an effect it had.



          The solution I found is below:



          enter image description here



          Here is my simulated annealing code (it might take a few tries before finding a zero-energy solution):



          edges[{perm1_, perm2_}] :=
          Join[
          Tuples[{perm1[[1 ;; 3]], perm2[[1 ;; 3]]}],
          Tuples[{perm1[[4 ;; 6]], perm2[[4 ;; 6]]}],
          Complement[
          Tuples[{perm1[[7 ;; 11]], perm2[[7 ;; 11]]}],
          Table[{perm1[[i]], perm2[[i]]}, {i, 7, 11}],
          Table[{perm1[[i]], perm2[[i + 1]]}, {i, 7, 10}]]];
          value[state_] := 102 - Length[Union @@ (edges /@ state)];
          randomPerm := {RandomSample[Range[11]], RandomSample[Range[11]]}
          newState := {{Range[11], Range[11]}, randomPerm, randomPerm};
          randomSwitch[state_] :=
          Module[{h = RandomInteger[{2, 3}], i = RandomInteger[{1, 2}], j, k,
          copy = state},
          {j, k} = RandomSample[Range[11], 2];
          copy[[h, i, {j, k}]] = Reverse[copy[[h, i, {j, k}]]];
          Return[copy];
          ]

          currentState = bestState = newState;
          currentEnergy = bestEnergy = value[currentState];
          temp = 1;
          While[Exp[-1/temp] > 1/1000,
          Do[
          nextState = randomSwitch[currentState];
          nextEnergy = value[nextState];
          If[nextEnergy < bestEnergy, bestState = nextState;
          bestEnergy = nextEnergy];
          prob = Exp[-((nextEnergy - currentEnergy)/temp)];
          If[RandomReal < prob, currentState = nextState;
          currentEnergy = nextEnergy];
          , {3000}];
          If[bestEnergy == 0, Break];
          temp *= 0.99; Print[{temp, currentEnergy}]
          ]
          Print["Done ", bestEnergy];





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          $endgroup$













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            1 Answer
            1






            active

            oldest

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            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            3












            $begingroup$

            Since I solved the other linked problem, I figured I might as well give simulated annealing a go on this one.



            The answer is also yes; in fact, here, we can find $3$ disjoint copies of $2K_{3,3} cup (K_{5,5} - P_{10})$. I added the extra edge in an attempt to make the problem a bit more constrained so that the solution would come out nicer, but I'm not sure how much of an effect it had.



            The solution I found is below:



            enter image description here



            Here is my simulated annealing code (it might take a few tries before finding a zero-energy solution):



            edges[{perm1_, perm2_}] :=
            Join[
            Tuples[{perm1[[1 ;; 3]], perm2[[1 ;; 3]]}],
            Tuples[{perm1[[4 ;; 6]], perm2[[4 ;; 6]]}],
            Complement[
            Tuples[{perm1[[7 ;; 11]], perm2[[7 ;; 11]]}],
            Table[{perm1[[i]], perm2[[i]]}, {i, 7, 11}],
            Table[{perm1[[i]], perm2[[i + 1]]}, {i, 7, 10}]]];
            value[state_] := 102 - Length[Union @@ (edges /@ state)];
            randomPerm := {RandomSample[Range[11]], RandomSample[Range[11]]}
            newState := {{Range[11], Range[11]}, randomPerm, randomPerm};
            randomSwitch[state_] :=
            Module[{h = RandomInteger[{2, 3}], i = RandomInteger[{1, 2}], j, k,
            copy = state},
            {j, k} = RandomSample[Range[11], 2];
            copy[[h, i, {j, k}]] = Reverse[copy[[h, i, {j, k}]]];
            Return[copy];
            ]

            currentState = bestState = newState;
            currentEnergy = bestEnergy = value[currentState];
            temp = 1;
            While[Exp[-1/temp] > 1/1000,
            Do[
            nextState = randomSwitch[currentState];
            nextEnergy = value[nextState];
            If[nextEnergy < bestEnergy, bestState = nextState;
            bestEnergy = nextEnergy];
            prob = Exp[-((nextEnergy - currentEnergy)/temp)];
            If[RandomReal < prob, currentState = nextState;
            currentEnergy = nextEnergy];
            , {3000}];
            If[bestEnergy == 0, Break];
            temp *= 0.99; Print[{temp, currentEnergy}]
            ]
            Print["Done ", bestEnergy];





            share|cite|improve this answer









            $endgroup$


















              3












              $begingroup$

              Since I solved the other linked problem, I figured I might as well give simulated annealing a go on this one.



              The answer is also yes; in fact, here, we can find $3$ disjoint copies of $2K_{3,3} cup (K_{5,5} - P_{10})$. I added the extra edge in an attempt to make the problem a bit more constrained so that the solution would come out nicer, but I'm not sure how much of an effect it had.



              The solution I found is below:



              enter image description here



              Here is my simulated annealing code (it might take a few tries before finding a zero-energy solution):



              edges[{perm1_, perm2_}] :=
              Join[
              Tuples[{perm1[[1 ;; 3]], perm2[[1 ;; 3]]}],
              Tuples[{perm1[[4 ;; 6]], perm2[[4 ;; 6]]}],
              Complement[
              Tuples[{perm1[[7 ;; 11]], perm2[[7 ;; 11]]}],
              Table[{perm1[[i]], perm2[[i]]}, {i, 7, 11}],
              Table[{perm1[[i]], perm2[[i + 1]]}, {i, 7, 10}]]];
              value[state_] := 102 - Length[Union @@ (edges /@ state)];
              randomPerm := {RandomSample[Range[11]], RandomSample[Range[11]]}
              newState := {{Range[11], Range[11]}, randomPerm, randomPerm};
              randomSwitch[state_] :=
              Module[{h = RandomInteger[{2, 3}], i = RandomInteger[{1, 2}], j, k,
              copy = state},
              {j, k} = RandomSample[Range[11], 2];
              copy[[h, i, {j, k}]] = Reverse[copy[[h, i, {j, k}]]];
              Return[copy];
              ]

              currentState = bestState = newState;
              currentEnergy = bestEnergy = value[currentState];
              temp = 1;
              While[Exp[-1/temp] > 1/1000,
              Do[
              nextState = randomSwitch[currentState];
              nextEnergy = value[nextState];
              If[nextEnergy < bestEnergy, bestState = nextState;
              bestEnergy = nextEnergy];
              prob = Exp[-((nextEnergy - currentEnergy)/temp)];
              If[RandomReal < prob, currentState = nextState;
              currentEnergy = nextEnergy];
              , {3000}];
              If[bestEnergy == 0, Break];
              temp *= 0.99; Print[{temp, currentEnergy}]
              ]
              Print["Done ", bestEnergy];





              share|cite|improve this answer









              $endgroup$
















                3












                3








                3





                $begingroup$

                Since I solved the other linked problem, I figured I might as well give simulated annealing a go on this one.



                The answer is also yes; in fact, here, we can find $3$ disjoint copies of $2K_{3,3} cup (K_{5,5} - P_{10})$. I added the extra edge in an attempt to make the problem a bit more constrained so that the solution would come out nicer, but I'm not sure how much of an effect it had.



                The solution I found is below:



                enter image description here



                Here is my simulated annealing code (it might take a few tries before finding a zero-energy solution):



                edges[{perm1_, perm2_}] :=
                Join[
                Tuples[{perm1[[1 ;; 3]], perm2[[1 ;; 3]]}],
                Tuples[{perm1[[4 ;; 6]], perm2[[4 ;; 6]]}],
                Complement[
                Tuples[{perm1[[7 ;; 11]], perm2[[7 ;; 11]]}],
                Table[{perm1[[i]], perm2[[i]]}, {i, 7, 11}],
                Table[{perm1[[i]], perm2[[i + 1]]}, {i, 7, 10}]]];
                value[state_] := 102 - Length[Union @@ (edges /@ state)];
                randomPerm := {RandomSample[Range[11]], RandomSample[Range[11]]}
                newState := {{Range[11], Range[11]}, randomPerm, randomPerm};
                randomSwitch[state_] :=
                Module[{h = RandomInteger[{2, 3}], i = RandomInteger[{1, 2}], j, k,
                copy = state},
                {j, k} = RandomSample[Range[11], 2];
                copy[[h, i, {j, k}]] = Reverse[copy[[h, i, {j, k}]]];
                Return[copy];
                ]

                currentState = bestState = newState;
                currentEnergy = bestEnergy = value[currentState];
                temp = 1;
                While[Exp[-1/temp] > 1/1000,
                Do[
                nextState = randomSwitch[currentState];
                nextEnergy = value[nextState];
                If[nextEnergy < bestEnergy, bestState = nextState;
                bestEnergy = nextEnergy];
                prob = Exp[-((nextEnergy - currentEnergy)/temp)];
                If[RandomReal < prob, currentState = nextState;
                currentEnergy = nextEnergy];
                , {3000}];
                If[bestEnergy == 0, Break];
                temp *= 0.99; Print[{temp, currentEnergy}]
                ]
                Print["Done ", bestEnergy];





                share|cite|improve this answer









                $endgroup$



                Since I solved the other linked problem, I figured I might as well give simulated annealing a go on this one.



                The answer is also yes; in fact, here, we can find $3$ disjoint copies of $2K_{3,3} cup (K_{5,5} - P_{10})$. I added the extra edge in an attempt to make the problem a bit more constrained so that the solution would come out nicer, but I'm not sure how much of an effect it had.



                The solution I found is below:



                enter image description here



                Here is my simulated annealing code (it might take a few tries before finding a zero-energy solution):



                edges[{perm1_, perm2_}] :=
                Join[
                Tuples[{perm1[[1 ;; 3]], perm2[[1 ;; 3]]}],
                Tuples[{perm1[[4 ;; 6]], perm2[[4 ;; 6]]}],
                Complement[
                Tuples[{perm1[[7 ;; 11]], perm2[[7 ;; 11]]}],
                Table[{perm1[[i]], perm2[[i]]}, {i, 7, 11}],
                Table[{perm1[[i]], perm2[[i + 1]]}, {i, 7, 10}]]];
                value[state_] := 102 - Length[Union @@ (edges /@ state)];
                randomPerm := {RandomSample[Range[11]], RandomSample[Range[11]]}
                newState := {{Range[11], Range[11]}, randomPerm, randomPerm};
                randomSwitch[state_] :=
                Module[{h = RandomInteger[{2, 3}], i = RandomInteger[{1, 2}], j, k,
                copy = state},
                {j, k} = RandomSample[Range[11], 2];
                copy[[h, i, {j, k}]] = Reverse[copy[[h, i, {j, k}]]];
                Return[copy];
                ]

                currentState = bestState = newState;
                currentEnergy = bestEnergy = value[currentState];
                temp = 1;
                While[Exp[-1/temp] > 1/1000,
                Do[
                nextState = randomSwitch[currentState];
                nextEnergy = value[nextState];
                If[nextEnergy < bestEnergy, bestState = nextState;
                bestEnergy = nextEnergy];
                prob = Exp[-((nextEnergy - currentEnergy)/temp)];
                If[RandomReal < prob, currentState = nextState;
                currentEnergy = nextEnergy];
                , {3000}];
                If[bestEnergy == 0, Break];
                temp *= 0.99; Print[{temp, currentEnergy}]
                ]
                Print["Done ", bestEnergy];






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                share|cite|improve this answer










                answered Dec 14 '18 at 19:18









                Misha LavrovMisha Lavrov

                46.1k656107




                46.1k656107






























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