It is the purpose of this paper to show that many of the enumerative techniques available for counting rooted plane trees may be extended to tree-rooted maps, that is, rooted maps in which a spanning tree is distinguished as root tree. For example, tree-rooted maps are enumerated by partition, and the average number of trees in a rooted map with n edges is determined. An enumerative similarity between Hamiltonian rooted maps (that is, rooted maps with a distinguished Hamiltonian polygon) and tree-rooted maps is discussed. A 1-1 correspondence is established between treerooted maps with n edges and Hamiltonian rooted trivalent maps with 2n + 1 vertices in which the root vertex is exceptional, being divalent, both of which are in 1-1 correspondence with non-separable Hamiltonian-rooted triangularized digons with n internal vertices, where both the latter are as defined in (2).
@article{10_4153_CJM_1967_010_x,
author = {Mullin, R. C.},
title = {On the {Enumeration} of {Tree-Rooted} {Maps}},
journal = {Canadian journal of mathematics},
pages = {174--183},
year = {1967},
volume = {19},
number = {1},
doi = {10.4153/CJM-1967-010-x},
url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1967-010-x/}
}
TY - JOUR
AU - Mullin, R. C.
TI - On the Enumeration of Tree-Rooted Maps
JO - Canadian journal of mathematics
PY - 1967
SP - 174
EP - 183
VL - 19
IS - 1
UR - http://geodesic.mathdoc.fr/articles/10.4153/CJM-1967-010-x/
DO - 10.4153/CJM-1967-010-x
ID - 10_4153_CJM_1967_010_x
ER -
%0 Journal Article
%A Mullin, R. C.
%T On the Enumeration of Tree-Rooted Maps
%J Canadian journal of mathematics
%D 1967
%P 174-183
%V 19
%N 1
%U http://geodesic.mathdoc.fr/articles/10.4153/CJM-1967-010-x/
%R 10.4153/CJM-1967-010-x
%F 10_4153_CJM_1967_010_x