What do temporal and spatial summations have in common?

Linear Algebra - summations & combinations of {2 x 2} finite positive-definite matrices in a {n x 2} matrix?

• Is there a way to calculate how many 2x2 matrices that can be generated by a larger {n x 2} matrix? Constraints: Must be combinations of rows Rows can be repeated ex: [13] 1 12 2 11 3 10 4 9 5 8 6 7 ex: Two 2x2 matrices that can be generated from the nx2 (6x2) matrix above would be: 2 11 3 10 or 3 10 6 7 for the matrix above, I figured out by hand that there "should" be about 15, however, I'm not sure on the accuracy of this figure...there may be more, there may be less. Is there a good algorithm for any give number "M"? -- in the case above M would be 13. ***Thanks for all of your help! I really appreciate it!!*** *****Basically I'm looking for an algorithm that would allow me to calculate how many 2x2 matrices can be generated from the larger matrix above, or in a more general sense, any nx2 matrix. However, the rows have to remain intact, you can only use combinations of the rows, the columns cannot be swapped either. ex 1 12 2 11 2 11 3 10 3 10 4 9 4 9 5 8 5 8 6 7 1 12 6 7 3 10 5 8 ...etc.

• Answer:

  I do not understand what you are asking. Please clarify more