Abstract :
Let A, B, C, and D be posets. Assume C and D are finite with a greatest element. Also assume that AC ≅B D. Then there exist posets E, X, Y , and Z such that A ≅E X, B ≅E Y , C≅Y ×Z, and D≅X×Z. If C≅D, then A≅B. This generalizes a theorem of Jónsson and McKenzie, who proved it when A and B were meet-semilattices.
