  Let $K_k$, $C_k$, $T_k$, and $P_{k}$ denote a complete graph on $k$ vertices,
a cycle on $k$ vertices, a tree on $k+1$ vertices, and a path on $k+1$
vertices, respectively. Let $K_{m}-H$ be the graph obtained from $K_{m}$ by
removing the edges set $E(H)$ of the graph $H$ ($H$ is a subgraph of $K_{m}$).
A sequence $S$ is potentially $K_{m}-H$-graphical if it has a realization
containing a $K_{m}-H$ as a subgraph. Let $\sigma(K_{m}-H, n)$ denote the
smallest degree sum such that every $n$-term graphical sequence $S$ with
$\sigma(S)\geq \sigma(K_{m}-H, n)$ is potentially $K_{m}-H$-graphical. In this
paper, we determine the values of $\sigma (K_{r+1}-H, n)$ for $n\geq 4r+10,
r\geq 3, r+1 \geq k \geq 4$ where $H$ is a graph on $k$ vertices which contains
a tree on 4 vertices but not contains a cycle on 3 vertices. We also determine
the values of $\sigma (K_{r+1}-P_2, n)$ for $n\geq 4r+8, r\geq 3$. There are a
number of graphs on $k$ vertices which containing a tree on 4 vertices but not
containing a cycle on 3 vertices (for example, the cycle on $k$ vertices, the
tree on $k$ vertices, and the complete 2-partite graph on $k$ vertices, etc).

Combinatorics