Let's say we have a 2 by 3 or a by b binary matrix. We want to determine the maximum number of matrices such that no matrix has all zeroes in one of its columns.
I started by counting the total number of matrices : 2^(axb).
Then I tried counting the number of matrices that don't make the fit.
The case in which the first column is all 0 gives the following : 2^(a)(b-1) Then I multiplied it with the number of columns. The formula is : 2^(a)(b-1)b
It doesn't give me the correct answer, and I think it's a problem related to permutations. How do I approach this?