binary tree


Characterizing (aleph_0,aleph_1)-graphs ★★★

Author(s): Diestel; Leader

Call a graph an $(\aleph_0,\aleph_1)$-\emph{graph} if it has a bipartition $(A,B)$ so that every vertex in $A$ has degree $\aleph_0$ and every vertex in $B$ has degree $\aleph_1$.

\begin{problem} Characterize the $(\aleph_0,\aleph_1)$-graphs. \end{problem}

Keywords: binary tree; infinite graph; normal spanning tree; set theory

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