The Dynamics of the Forest Graph Operator

In 1966, Cummins introduced the “tree graph”: the tree graph T(G) of a graph G (possibly infinite) has all its spanning trees as vertices, and distinct such trees correspond to adjacent vertices if they differ in just one edge, i.e., two spanning trees T1 and T2 are adjacent if T2 = T1 − e + f for s...

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Main Authors: Dara Suresh, Hegde S.M., Deva Venkateshwarlu, Rao S.B., Zaslavsky Thomas
Format: Article
Language:English
Published: University of Zielona Góra 2016-11-01
Series:Discussiones Mathematicae Graph Theory
Subjects:
Online Access:https://doi.org/10.7151/dmgt.1901
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author Dara Suresh
Hegde S.M.
Deva Venkateshwarlu
Rao S.B.
Zaslavsky Thomas
author_facet Dara Suresh
Hegde S.M.
Deva Venkateshwarlu
Rao S.B.
Zaslavsky Thomas
author_sort Dara Suresh
collection DOAJ
description In 1966, Cummins introduced the “tree graph”: the tree graph T(G) of a graph G (possibly infinite) has all its spanning trees as vertices, and distinct such trees correspond to adjacent vertices if they differ in just one edge, i.e., two spanning trees T1 and T2 are adjacent if T2 = T1 − e + f for some edges e ∈ T1 and f ∉ T1. The tree graph of a connected graph need not be connected. To obviate this difficulty we define the “forest graph”: let G be a labeled graph of order α, finite or infinite, and let N(G) be the set of all labeled maximal forests of G. The forest graph of G, denoted by F(G), is the graph with vertex set N(G) in which two maximal forests F1, F2 of G form an edge if and only if they differ exactly by one edge, i.e., F2 = F1 − e + f for some edges e ∈ F1 and f ∉ F1. Using the theory of cardinal numbers, Zorn’s lemma, transfinite induction, the axiom of choice and the well-ordering principle, we determine the F-convergence, F-divergence, F-depth and F-stability of any graph G. In particular it is shown that a graph G (finite or infinite) is F-convergent if and only if G has at most one cycle of length 3. The F-stable graphs are precisely K3 and K1. The F-depth of any graph G different from K3 and K1 is finite. We also determine various parameters of F(G) for an infinite graph G, including the number, order, size, and degree of its components.
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spelling doaj.art-366fdc434fbd46cab4477f05c69704c42023-09-02T21:42:49ZengUniversity of Zielona GóraDiscussiones Mathematicae Graph Theory2083-58922016-11-0136489991310.7151/dmgt.1901dmgt.1901The Dynamics of the Forest Graph OperatorDara Suresh0Hegde S.M.1Deva Venkateshwarlu2Rao S.B.3Zaslavsky Thomas4Department of Mathematical and Computational Sciences National Institute of Technology Karnataka Surathkal, Mangalore-575025, IndiaDepartment of Mathematical and Computational Sciences National Institute of Technology Karnataka Surathkal, Mangalore-575025, IndiaC.R. Rao Advanced Institute of Mathematics, Statistics and Computer Science Hyderabad-500 046, IndiaC. R. Rao Advanced Institute of Mathematics, Statistics and Computer Science Hyderabad-500 046, IndiaDepartment of Mathematical Sciences, Binghamton University Binghamton, NY, 13902-6000, United States of AmericaIn 1966, Cummins introduced the “tree graph”: the tree graph T(G) of a graph G (possibly infinite) has all its spanning trees as vertices, and distinct such trees correspond to adjacent vertices if they differ in just one edge, i.e., two spanning trees T1 and T2 are adjacent if T2 = T1 − e + f for some edges e ∈ T1 and f ∉ T1. The tree graph of a connected graph need not be connected. To obviate this difficulty we define the “forest graph”: let G be a labeled graph of order α, finite or infinite, and let N(G) be the set of all labeled maximal forests of G. The forest graph of G, denoted by F(G), is the graph with vertex set N(G) in which two maximal forests F1, F2 of G form an edge if and only if they differ exactly by one edge, i.e., F2 = F1 − e + f for some edges e ∈ F1 and f ∉ F1. Using the theory of cardinal numbers, Zorn’s lemma, transfinite induction, the axiom of choice and the well-ordering principle, we determine the F-convergence, F-divergence, F-depth and F-stability of any graph G. In particular it is shown that a graph G (finite or infinite) is F-convergent if and only if G has at most one cycle of length 3. The F-stable graphs are precisely K3 and K1. The F-depth of any graph G different from K3 and K1 is finite. We also determine various parameters of F(G) for an infinite graph G, including the number, order, size, and degree of its components.https://doi.org/10.7151/dmgt.1901forest graph operatorgraph dynamics
spellingShingle Dara Suresh
Hegde S.M.
Deva Venkateshwarlu
Rao S.B.
Zaslavsky Thomas
The Dynamics of the Forest Graph Operator
Discussiones Mathematicae Graph Theory
forest graph operator
graph dynamics
title The Dynamics of the Forest Graph Operator
title_full The Dynamics of the Forest Graph Operator
title_fullStr The Dynamics of the Forest Graph Operator
title_full_unstemmed The Dynamics of the Forest Graph Operator
title_short The Dynamics of the Forest Graph Operator
title_sort dynamics of the forest graph operator
topic forest graph operator
graph dynamics
url https://doi.org/10.7151/dmgt.1901
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