WebWe examine the question of when two consecutive levels in a product of ω-chains form an ordered set such that for any antichain, there is a maximal antichain disjoint from it. … Webcardinal m+1. The antichain M consisting of all maximal elements in P is clearly non-empty since the maximal element of every maximal chain belongs to M. Further, no chain in P\M has cardinal m. For assume, on the contrary, that xl < x2 < . . . < mXnt X; 1E P\M ( 1 <_! k :_! m)*-Then, since this chain has cardinal m, it is maximal and so xmeM ...
Maximal antichains of subsets II: Constructions - ResearchGate
Webantichain. Since #(C i ∩A) ≤ 1, we have k ≥ #A. Thus: Proposition. Let k be the least integer such that P is a union of k chains. Let m be the size of the largest antichain of P. Then k ≥ m. Theorem (Robert Dilworth, 1950). k = m. (forerunner of the … Web28 dec. 2024 · Say x ⪯ y if s ≤ t and i s − k ≤ j t − k for all 0 ≤ k ≤ s − 1. I want to know the formula of the size of maximal antichain according to n, the maximal cardinality of set in which any two distinct elements are incomparable. Here are some conclusions I have obtained. Denote S n as the size of maximal antichain, then S n ≤ ( n ... kennebec learning center
order theory - Can one characterize maximal antichains in terms …
Web4 jun. 2024 · Maximal antichains of subsets II: Constructions Jerrold R. Griggs, Thomas Kalinowski, Uwe Leck, Ian T. Roberts, Michael Schmitz This is the second in a sequence of three papers investigating the question for which positive integers there exists a maximal antichain of size in the Boolean lattice (the power set of , ordered by inclusion). WebDilworth's theorem states that, in any finite partially ordered set, the largest antichain has the same size as the smallest chain decomposition. Here, the size of the antichain is its … Web4 dec. 2024 · (1) = (2): In any finite partially ordered set, the number of antichains is equal to the number of lower sets. If L is a lower set, the set a ( L) of all maximal elements of L is an antichain; if A is an antichain, the set ℓ ( A) = { x: ∃ a ∈ A ( x ∈ a) } is a lower set; the maps a and ℓ are easily seen to be inverses. kennebec maine county registry of deeds