Let $G_X = (X, \mathcal{E}_X)$ be a D778: Graph such that

(i)	$G_E = (E, \mathcal{E}_E)$ is a D2737: Subgraph of $G_X$

Then $G_E$ is a spanning subgraph of $G_X$ if and only if \begin{equation} E = X \end{equation}