Orthogonal partitions.(English)Zbl 0794.03064

Summary: We introduce and study a notion of orthogonal partitions of $$\omega$$ which is in a certain sense dual to the notion of almost disjoint subsets of $$\omega$$. We consider maximal families of pairwise orthogonal partitions and dual matrices.

MSC:

 03E05 Other combinatorial set theory 03E35 Consistency and independence results 05A17 Combinatorial aspects of partitions of integers 03E50 Continuum hypothesis and Martin’s axiom 05A18 Partitions of sets
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