1983/07/01 by Ron Aharoni, R. Aharoni, C. St. J. A. Nash‐Williams +3 · 3 citations
Mathematics · Computer Science · #Advanced Topology and Set Theory #Computability, Logic, AI Algorithms #Limits and Structures in Graph Theory
paper · doi:10.1112/plms/s3-47.1.43
We present a necessary and sufficient condition for a family of sets to possess a transversal. Its form follows that of P. Hall's theorem: a family has a transversal if and only if it does not contain one of a set of ‘forbidden’ substructures.