Premium
Cutpoints and the chromatic polynomial
Author(s) -
Whitehead Earl Glen,
Zhao LianChang
Publication year - 1984
Publication title -
journal of graph theory
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 54
eISSN - 1097-0118
pISSN - 0364-9024
DOI - 10.1002/jgt.3190080305
Subject(s) - chromatic polynomial , mathematics , combinatorics , chromatic scale , friendship graph , windmill graph , multiplicity (mathematics) , foster graph , uniqueness , simple graph , graph , discrete mathematics , tutte polynomial , polynomial , voltage graph , line graph , mathematical analysis
We prove that the multiplicity of the root 1 in the chromatic polynomial of a simple graph G is equal to the number of nontrivial blocks in G . In particular, a connected simple graph G has a cutpoint if and only if its chromatic polynomial is divisible by (λ – 1) 2 . We apply this theorem to obtain some chromatic equivalence and uniqueness results.
Accelerating Research
Robert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom
Address
John Eccles HouseRobert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom