Name the problem: dividing indexed coins in bins












1














Does any of you know the name of the problem described below? I am especially interested in possible generalizations of this problem.



I looked through my textbooks on combinatorics but could not find a similar problem.



Problem Statement.
I have 36 different coins. Each side has a number printed on it ranging from 1 to 6.



With notation {NumberSideA, NumberSideB} this would give:



{1,1}, {1,2}, ..., {1,6},

{2,1}, {2,2}, ..., {2,6},

...,

{6,1}, {6,2}, ..., {6,6}.



I want to divide all of these into a number of bins such that in each bin, there are at most 4 different indices on Side A and at most 4 different indices on Side B.
Furthermore, any combination of 2 bins should contain coins with at most 5 different indices on Side A and at most 5 different indices on side B.




  • What is the minimum number of bins for which this is possible?










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  • you can think about partitioning your grid. And by grid I mean the 6x6 matrix the problem admits. This males it clear it can be done in 4 bins. But I don’t know if that will necessarily give you the min
    – T. Ford
    Dec 19 '18 at 15:44










  • Six bins is minimal as shown in my completely rewritten answer.
    – Daniel Mathias
    Jan 4 at 17:14
















1














Does any of you know the name of the problem described below? I am especially interested in possible generalizations of this problem.



I looked through my textbooks on combinatorics but could not find a similar problem.



Problem Statement.
I have 36 different coins. Each side has a number printed on it ranging from 1 to 6.



With notation {NumberSideA, NumberSideB} this would give:



{1,1}, {1,2}, ..., {1,6},

{2,1}, {2,2}, ..., {2,6},

...,

{6,1}, {6,2}, ..., {6,6}.



I want to divide all of these into a number of bins such that in each bin, there are at most 4 different indices on Side A and at most 4 different indices on Side B.
Furthermore, any combination of 2 bins should contain coins with at most 5 different indices on Side A and at most 5 different indices on side B.




  • What is the minimum number of bins for which this is possible?










share|cite|improve this question
























  • you can think about partitioning your grid. And by grid I mean the 6x6 matrix the problem admits. This males it clear it can be done in 4 bins. But I don’t know if that will necessarily give you the min
    – T. Ford
    Dec 19 '18 at 15:44










  • Six bins is minimal as shown in my completely rewritten answer.
    – Daniel Mathias
    Jan 4 at 17:14














1












1








1







Does any of you know the name of the problem described below? I am especially interested in possible generalizations of this problem.



I looked through my textbooks on combinatorics but could not find a similar problem.



Problem Statement.
I have 36 different coins. Each side has a number printed on it ranging from 1 to 6.



With notation {NumberSideA, NumberSideB} this would give:



{1,1}, {1,2}, ..., {1,6},

{2,1}, {2,2}, ..., {2,6},

...,

{6,1}, {6,2}, ..., {6,6}.



I want to divide all of these into a number of bins such that in each bin, there are at most 4 different indices on Side A and at most 4 different indices on Side B.
Furthermore, any combination of 2 bins should contain coins with at most 5 different indices on Side A and at most 5 different indices on side B.




  • What is the minimum number of bins for which this is possible?










share|cite|improve this question















Does any of you know the name of the problem described below? I am especially interested in possible generalizations of this problem.



I looked through my textbooks on combinatorics but could not find a similar problem.



Problem Statement.
I have 36 different coins. Each side has a number printed on it ranging from 1 to 6.



With notation {NumberSideA, NumberSideB} this would give:



{1,1}, {1,2}, ..., {1,6},

{2,1}, {2,2}, ..., {2,6},

...,

{6,1}, {6,2}, ..., {6,6}.



I want to divide all of these into a number of bins such that in each bin, there are at most 4 different indices on Side A and at most 4 different indices on Side B.
Furthermore, any combination of 2 bins should contain coins with at most 5 different indices on Side A and at most 5 different indices on side B.




  • What is the minimum number of bins for which this is possible?







combinatorics






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edited Dec 19 '18 at 17:23







hpmor123

















asked Dec 19 '18 at 13:57









hpmor123hpmor123

63




63












  • you can think about partitioning your grid. And by grid I mean the 6x6 matrix the problem admits. This males it clear it can be done in 4 bins. But I don’t know if that will necessarily give you the min
    – T. Ford
    Dec 19 '18 at 15:44










  • Six bins is minimal as shown in my completely rewritten answer.
    – Daniel Mathias
    Jan 4 at 17:14


















  • you can think about partitioning your grid. And by grid I mean the 6x6 matrix the problem admits. This males it clear it can be done in 4 bins. But I don’t know if that will necessarily give you the min
    – T. Ford
    Dec 19 '18 at 15:44










  • Six bins is minimal as shown in my completely rewritten answer.
    – Daniel Mathias
    Jan 4 at 17:14
















you can think about partitioning your grid. And by grid I mean the 6x6 matrix the problem admits. This males it clear it can be done in 4 bins. But I don’t know if that will necessarily give you the min
– T. Ford
Dec 19 '18 at 15:44




you can think about partitioning your grid. And by grid I mean the 6x6 matrix the problem admits. This males it clear it can be done in 4 bins. But I don’t know if that will necessarily give you the min
– T. Ford
Dec 19 '18 at 15:44












Six bins is minimal as shown in my completely rewritten answer.
– Daniel Mathias
Jan 4 at 17:14




Six bins is minimal as shown in my completely rewritten answer.
– Daniel Mathias
Jan 4 at 17:14










2 Answers
2






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oldest

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0














The problem is a variation of Latin Square. It is equivalent to ask how many colors are needed to color a 6x6 grid lattice such that:




  1. each color occupies at most 4 grids of any row and any column.

  2. no two color together occupies a whole row or a whole column.


This certainly cannot be done with two colors. The following example shows with 3 colors, this is possible.
enter image description here






share|cite|improve this answer





























    0
















    • What is the minimum number of bins for which this is possible?




    My previous claim that 7 bins is minimal was incorrect. I wrote a short program in C to search for a solution in 6 bins. This is the output:



    0 0 0 1 1 2
    0 0 0 1 1 3
    0 0 0 4 4 5
    1 4 5 1 1 5
    2 2 3 3 4 2
    2 2 3 3 5 2


    The numbers in this grid indicate which bin each coin is in. The indices for the coins are the (x, y) column and row values (not shown). This is known to be a minimal solution because the program would not have assigned any coin to the sixth bin if could be placed into one of the first five subject to the stated restrictions.






    share|cite|improve this answer























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      2 Answers
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      2 Answers
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      0














      The problem is a variation of Latin Square. It is equivalent to ask how many colors are needed to color a 6x6 grid lattice such that:




      1. each color occupies at most 4 grids of any row and any column.

      2. no two color together occupies a whole row or a whole column.


      This certainly cannot be done with two colors. The following example shows with 3 colors, this is possible.
      enter image description here






      share|cite|improve this answer


























        0














        The problem is a variation of Latin Square. It is equivalent to ask how many colors are needed to color a 6x6 grid lattice such that:




        1. each color occupies at most 4 grids of any row and any column.

        2. no two color together occupies a whole row or a whole column.


        This certainly cannot be done with two colors. The following example shows with 3 colors, this is possible.
        enter image description here






        share|cite|improve this answer
























          0












          0








          0






          The problem is a variation of Latin Square. It is equivalent to ask how many colors are needed to color a 6x6 grid lattice such that:




          1. each color occupies at most 4 grids of any row and any column.

          2. no two color together occupies a whole row or a whole column.


          This certainly cannot be done with two colors. The following example shows with 3 colors, this is possible.
          enter image description here






          share|cite|improve this answer












          The problem is a variation of Latin Square. It is equivalent to ask how many colors are needed to color a 6x6 grid lattice such that:




          1. each color occupies at most 4 grids of any row and any column.

          2. no two color together occupies a whole row or a whole column.


          This certainly cannot be done with two colors. The following example shows with 3 colors, this is possible.
          enter image description here







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Dec 20 '18 at 14:14









          ablmfablmf

          2,37442352




          2,37442352























              0
















              • What is the minimum number of bins for which this is possible?




              My previous claim that 7 bins is minimal was incorrect. I wrote a short program in C to search for a solution in 6 bins. This is the output:



              0 0 0 1 1 2
              0 0 0 1 1 3
              0 0 0 4 4 5
              1 4 5 1 1 5
              2 2 3 3 4 2
              2 2 3 3 5 2


              The numbers in this grid indicate which bin each coin is in. The indices for the coins are the (x, y) column and row values (not shown). This is known to be a minimal solution because the program would not have assigned any coin to the sixth bin if could be placed into one of the first five subject to the stated restrictions.






              share|cite|improve this answer




























                0
















                • What is the minimum number of bins for which this is possible?




                My previous claim that 7 bins is minimal was incorrect. I wrote a short program in C to search for a solution in 6 bins. This is the output:



                0 0 0 1 1 2
                0 0 0 1 1 3
                0 0 0 4 4 5
                1 4 5 1 1 5
                2 2 3 3 4 2
                2 2 3 3 5 2


                The numbers in this grid indicate which bin each coin is in. The indices for the coins are the (x, y) column and row values (not shown). This is known to be a minimal solution because the program would not have assigned any coin to the sixth bin if could be placed into one of the first five subject to the stated restrictions.






                share|cite|improve this answer


























                  0












                  0








                  0








                  • What is the minimum number of bins for which this is possible?




                  My previous claim that 7 bins is minimal was incorrect. I wrote a short program in C to search for a solution in 6 bins. This is the output:



                  0 0 0 1 1 2
                  0 0 0 1 1 3
                  0 0 0 4 4 5
                  1 4 5 1 1 5
                  2 2 3 3 4 2
                  2 2 3 3 5 2


                  The numbers in this grid indicate which bin each coin is in. The indices for the coins are the (x, y) column and row values (not shown). This is known to be a minimal solution because the program would not have assigned any coin to the sixth bin if could be placed into one of the first five subject to the stated restrictions.






                  share|cite|improve this answer
















                  • What is the minimum number of bins for which this is possible?




                  My previous claim that 7 bins is minimal was incorrect. I wrote a short program in C to search for a solution in 6 bins. This is the output:



                  0 0 0 1 1 2
                  0 0 0 1 1 3
                  0 0 0 4 4 5
                  1 4 5 1 1 5
                  2 2 3 3 4 2
                  2 2 3 3 5 2


                  The numbers in this grid indicate which bin each coin is in. The indices for the coins are the (x, y) column and row values (not shown). This is known to be a minimal solution because the program would not have assigned any coin to the sixth bin if could be placed into one of the first five subject to the stated restrictions.







                  share|cite|improve this answer














                  share|cite|improve this answer



                  share|cite|improve this answer








                  edited Jan 4 at 17:11

























                  answered Dec 24 '18 at 3:36









                  Daniel MathiasDaniel Mathias

                  3856




                  3856






























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