
doi: 10.1007/bf01203369
For elements p, p' of a poset P, write \(p\sim p'\) provided \(xp_ 1...p_ 0\) and \(p_ i\nleq q_ j\) for \(j\neq i,i-1(mod n)\). Theorem: If \(S=P{\dot \cup}Q\) is bipartite and no element is part of an infinite number of crowns, then FL(S), the lattice freely generated by S, is projective. Theorem: Suppose P\({\dot \cup}Q\) is embeddable in a free lattice. If P/\(\sim\) is finite, then \(| Q/\sim | \leq 2^{| P/\sim |}\); if P/\(\sim\) is infinite, then \(| Q/\sim | =| P/\sim |\). Theorem: Suppose that P\({\dot \cup}Q\) is embeddable in a free lattice, that \(\sim\) is equality, and that \(| P| =| Q| =\beta\), a regular uncountable cardinal. Then there exist \(P^*\subset P\), \(Q^*\subset Q\) such that \(| P^*| =| Q^*| =\beta\) and \(P^*\cup Q^*\) is an antichain.
embeddable in a free lattice, Free lattices, projective lattices, word problems, Partial orders, general, crowns, poset, antichains, bipartite poset
embeddable in a free lattice, Free lattices, projective lattices, word problems, Partial orders, general, crowns, poset, antichains, bipartite poset
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