On an identity for the cycle indices of rooted tree automorphism groups
The electronic journal of combinatorics, Tome 13 (2006)
This note deals with a formula due to G. Labelle for the summed cycle indices of all rooted trees, which resembles the well-known formula for the cycle index of the symmetric group in some way. An elementary proof is provided as well as some immediate corollaries and applications, in particular a new application to the enumeration of $k$-decomposable trees. A tree is called $k$-decomposable in this context if it has a spanning forest whose components are all of size $k$.
@article{10_37236_1152,
author = {Stephan G. Wagner},
title = {On an identity for the cycle indices of rooted tree automorphism groups},
journal = {The electronic journal of combinatorics},
year = {2006},
volume = {13},
doi = {10.37236/1152},
zbl = {1113.05050},
url = {http://geodesic.mathdoc.fr/articles/10.37236/1152/}
}
Stephan G. Wagner. On an identity for the cycle indices of rooted tree automorphism groups. The electronic journal of combinatorics, Tome 13 (2006). doi: 10.37236/1152
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