Consider a general nonconvex QP $x^\top Qx$. This can be linearized in an extended space by using the variable $Y=xx^\top$.
Now a valid inequality $a^\top x \le b$ can be strengthend by the RLT procedure by multiplying with some $x_j$ to obtain $a^\top y \le bx_j$. See for example here.
Are there other approaches than RLT in the context of nonconvex qps to strengthen a given inequality?