“…Many proofs of Dilworth's Theorem are known [5,9,10,14,17,18]. Among them, the argument provided by Fulkerson [10] is straightforward, by which a bipartite graph G S with bipartite (V 1 , V 2 ) for S = {a 1 , a 2 , ...,a n } is constructed, where V 1 = {x 1 , x 2 , ..., x n }, V 2 = {y 1 , y 2 , ..., y n } and an edge joining x i V 1 to y j V 2 whenever a i a j .…”