Some Results on $k$-Tur\'{a}n-good Graphs

TL;DR

This paper investigates the properties of $k$-Turán-good graphs, constructing new classes and proving that certain paths are $k$-Turán-good for all $k extgreater=4$, advancing understanding of extremal graph configurations.

Contribution

The paper introduces new classes of $k$-Turán-good graphs and proves that specific paths are $k$-Turán-good for all $k extgreater=4$, expanding the known classes.

Findings

Constructed new classes of $k$-Turán-good graphs.

Proved $P_4$ and $P_5$ are $k$-Turán-good for $k extgreater=4$.

Enhanced understanding of extremal properties of $k$-Turán-good graphs.

Abstract

For a graph $H$ and a $k$-chromatic graph $F,$ if the Tur\'an graph $T_{k-1}(n)$ has the maximum number of copies of $H$ among all $n$-vertex $F$-free graphs (for $n$ large enough), then $H$ is called $F$-Tur\'an-good, or $k$-Tur\'an-good for short if $F$ is $K_k.$ In this paper, we construct some new classes of $k$-Tur\'an-good graphs and prove that $P_4$ and $P_5$ are $k$-Tur\'an-good for $k\ge4.$