Fig. 1
From: An improved Four-Russians method and sparsified Four-Russians algorithm for RNA folding
An example of how a solution matrix L is broken down into submatrices. Using the extended vector notation we can say that cell L[i, j] belongs to the vector \(L[K_{g_i},j]\) as well as submatrix \(L[I_{g_i},K_{g_j}]\). We partition the solution matrix L into \(O(n^2/q)\) vectors of size O(q) and \(O(n^2/q^2)\) submatrices, of size \(O(q^2)\)