“…, S i−1 }. For example, the increasing subsequences of the permutation π = (5,6,2,8,1,9,7,4,3) are S 1 = (5,6,8,9), S 2 = (2, 7) since π ′ = π\S 1 = (2, 1, 7, 4, 3), S 3 = (1, 4), and S 4 = (3), while its decreasing subsequences are S 1 = (5, 2, 1), S 2 = (6, 4, 3), S 3 = (8, 7), and S 4 = (9).…”