Abstract
Several results concerning contractible and removable edges in 3-connected finite graphs are extended to infinite graphs. First, we prove that every 3-connected locally finite infinite graph has infinitely many removable edges. Next, we prove that for any 3-connected graph \(G\), if \(x\) is a finite degree vertex in \(G\) and is not incident to any contractible edges, then \(G-x\) is a finite cycle or contains a border pair. As a result, every 3-connected locally finite infinite graph contains infinitely many contractible edges. Lastly, it is shown that for any 3-connected locally finite infinite graph \(G\) which is triangle-free or has minimum degree at least 4, the closure of the subgraph induced by all the contractible edges in the Freudenthal compactification of \(G\) is topologically 2-connected.
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Chan, T.L. Contractible and Removable Edges in 3-Connected Infinite Graphs. Graphs and Combinatorics 31, 871–883 (2015). https://doi.org/10.1007/s00373-014-1431-3
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DOI: https://doi.org/10.1007/s00373-014-1431-3