fix: 4.7 图网络 latex

4.人工智能/4.7图网络略述（intro&GCN）.md

@@ -47,9 +47,9 @@ $$
 $$
 L_{ij}^{sym}=
 \begin{cases}
-1 \quad\quad\quad\quad\quad\quad i=j{\color{red}{\backslash and}}deg(v_i)\ne0\\
+1 \quad\quad\quad\quad\quad\quad\quad\enspace\thinspace \left ( i=j\right ) \cup \left ( deg(v_i)\ne0 \right ) \\
--\frac{1}{\sqrt{deg(v_i)deg(v_j)}}i\ne j{\color{red}{\backslash and}}v_i adj v_j \\
+-\frac{1}{\sqrt{deg(v_i)deg(v_j)}} \qquad \left ( i\ne j \right ) \cup \left ( v_i adj v_j \right ) \\
-0 \quad\quad\quad\quad\quad\quad else.
+0 \quad\quad\quad\quad\quad\quad\quad\;\;\; else.
 \end{cases}
 $$