Figure 8

The basic intersection staircase shown in grey must be refined since there are rectangles like Pi ∈ P^r(t) and r ∈ R^r(t) which have not been considered before in the runs for t' and which reduce the basic intersection staircase such that a lower staircase shown in darkgrey remains. Hence for the computation of the maximal cliques regarding t we have to reduce the area of the upper half only by the refined staircase.