All Questions
6
questions with no upvoted or accepted answers
2
votes
0
answers
82
views
Revealed preference rank rule: variation on horse race problem
Suppose there are x number of objects to be ranked. Then there are x[(x-1)/2] possible comparisons of these objects. Only subsets of x can be evaluated for comparisons and there is always one most and ...
- 147
2
votes
0
answers
512
views
How to distribute 5-digit numbers in 5x5 matrices
I have 98000 5-digit numbers, from 00001 to 98000. I need to distribute these 98000 numbers in 14000 5x5 matrices.
A matrix cell must contain only a digit from 0 to 9.
Each matrix must receive 7 ...
- 121
2
votes
0
answers
651
views
Does a matrix represent a bijection
We have a square binary matrix that represents a connection from rows to columns. Is there a way to tell if a bijection exists (other than checking for all possible bijections and iterating through ...
- 404
0
votes
0
answers
34
views
How to permute the rows and cols of a matrix to maximize the set of pivots?
Given an $m\times n$ matrix $A$, how can I find permutations $\sigma,\tau$, such that for the matrix $B=A[\sigma,\tau]$ with shuffled columns and rows, the number of nonzero entries that have zeros ...
- 10.7k
0
votes
0
answers
111
views
Summing the product of combinations of matrix elements
I have a situation where I have an $NxN$ matrix $A$ where each element $a_{i,j}\in\mathbb{R}_{\leq 0}$. I would like to consider the set of all collections of elements such that each collection of $N$ ...
- 121
0
votes
1
answer
399
views
number of ways to fill a 2D grid
We have a 2D grid with n rows and m columns, we can fill it with numbers between 1 and k (both inclusive). Only condition is that for each r such that 1<=r<=k ,no two rows must have exactly the ...
- 315