This is due to the fact that the number of FPs can range from zero to the size of negative labels, and the number of FNs can range from zero to the number of positive labels.
the loss term can take O(N 2 L 2 ) different values which can Algorithm 3 Finding Y * : Local Search 1: procedure OPT-LOSSLAG(Λ, Y) 2: Initialise (f p, f n) on the grid 5: for ((f p , f n ) ∈ Neigbours(f p, f n) do 7: : if loss (f p,f n) > loss (f p ,f n ) then 10: else 12: 13: 14: return { Y corresponding to (f p, f n) } be represented on a two-dimensional grid.