Normal Spanning Trees, Aronszajn Trees and Excluded Minors
نویسندگان
چکیده
منابع مشابه
Normal Spanning Trees, Aronszajn Trees and Excluded Minors
We prove that a connected infinite graph has a normal spanning tree (the infinite analogue of a depth-first search tree) if and only if it has no minor obtained canonically from either an (א0,א1)-regular bipartite graph or an order-theoretic Aronszajn tree. This disproves Halin’s conjecture that only the first of these obstructions was needed to characterize the graphs with normal spanning tree...
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This survey describes the contribution of N. Aronszajn to set theory: the construction of an Aronszajn tree. We would like to explain to the non-specialist in set theory what is an Aronszajn tree, how it is constructed, and why it occupies such a central place in set theory. In fact, we describe two constructions: the classical one, and a newer construction of a canonical Aronszajn tree due to ...
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ژورنال
عنوان ژورنال: Journal of the London Mathematical Society
سال: 2001
ISSN: 0024-6107
DOI: 10.1112/s0024610700001708