Nicola Lorenz, A Minor Characterisation of Normally Spanned Sets of Vertices
Room B332 IBS (기초과학연구원)A rooted spanning tree of a graph $G$ is called normal if the endvertices of all edges of $G$ are comparable in the tree order. It is well known that every finite connected graph has a normal spanning tree (also known as depth-first search tree). Also, all countable graphs have normal spanning trees, but uncountable …