Graph Theory Seminar - Ryan Martin

Tuesday, May 10, 2016 2:30 pm - 2:30 pm EDT (GMT -04:00)

Title: On the edit distance of powers of cycles

Speaker: Ryan Martin
Affiliation: Iowa State University
Room: MC 5479

Abstract: The edit distance between two graphs on the same labeled vertex set is defined to be the size of the symmetric difference of the edge
sets, divided by ${n\choose\lfloor n/2\rfloor}$. The edit distance function of a hereditary property $\mathcal{H}$ is a function of $p\in[0,1]$ that measures, in the limit, the maximum normalized edit distance between a graph of density $p$ and $\mathcal{H}$. It is also, again in the limit, the edit distance of the Erd\H{o}s-R\'{e}nyi random graph $G(n, p)$ from $\mathcal{H}$. In this talk, we address the edit distance function for ${\rm Forb}(H)$, where $H=C^t_h$, the $t^{\rm th}$ power of the cycle of length $h$. For $h\ge 2t(t + 1) + 1$ and $h$ not divisible by $t + 1$, we determine the function for all values of $p$. For $h \ge 2t(t + 1) + 1$ and $h$ divisible by $t + 1$, the function is obtained for all but small values of $p$. We also obtain some results for smaller values of $h$.

The proof methods involve a weighted version of P\'{o}sa's classic
argument on Hamilton cycles. This weighted version has complications that do not occur in the unweighted case. This is joint work with Zhanar
Berikkyzy and Chelsea Peck.