Meno:  Ján


Priezvisko:  Mazák


Názov:  Circular Chromatic Index of Snarks


Vedúci:  Prof. RNDr. Martin ©koviera, PhD.


Rok:  2007


Blok:  MMI


Kµúčové slová:  snark, circular chromatic index, Blanusa snark


Abstrakt:  A circular $r$edgecoloring of a graph $G$ is a mapping $c:E(G)\to [0,r)$ such that for any two adjacent edges $e$ and $f$ of $G$ we have $1\le c(e)c(f)\le r1$. The circular chromatic index $\chi_c'(G)$ is the infimum of all real numbers $r$ such that $G$ has a circular $r$edgecoloring.
We establish a general lower bound for the circular chromatic index of a snark $G$ depending only on the order of $G$. This bound is asymptotically tight.
We also determine the exact value of the circular chromatic index of the generalized Blanu\v sa snarks.
In this case, the index takes infinitely many values and can be arbitrarily close to $3$. The generalized Blanu\v sa snarks are the first explicit class of snarks with this property.

