diff --git a/SM3中的FF2和GG2函数.md b/SM3中的FF2和GG2函数.md
index 541a9b0..b8c7fa3 100644
--- a/SM3中的FF2和GG2函数.md
+++ b/SM3中的FF2和GG2函数.md
@@ -40,7 +40,7 @@ GG2等价公式初次见于[Intel® Integrated Performance Primitives Cryptograp
 
 # 证明
 Ask help https://math.stackexchange.com/questions/4775054/how-to-prove-below-two-logic-formulas  
-GG2(X,Y,Z)
+$GG2(X,Y,Z)$  
 = $(X \land Y) \bigoplus (\lnot X \land Z)$  
 = $(\lnot (X \land Y) \land (\lnot X \land Z)) \lor ((X \land Y) \land (\lnot (\lnot X \land Z)))$   
 = $((\lnot X \lor \lnot Y) \land (\lnot X \land Z)) \lor ((X \land Y) \land (X \lor \lnot Z))$