From 8d06daf45f732cc0f2a2828df147477cfcf85cdc Mon Sep 17 00:00:00 2001
From: mba1398 <26516464+mba1398@users.noreply.github.com>
Date: Sat, 3 Jul 2021 10:34:26 +0800
Subject: [PATCH] =?UTF-8?q?Update=20ch04:=20=E9=9B=86=E5=90=88=E8=BF=90?=
 =?UTF-8?q?=E7=AE=97.md?=
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---
 ch04: 集合运算.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/ch04: 集合运算.md b/ch04: 集合运算.md
index bf264eb..e7aeac1 100644
--- a/ch04: 集合运算.md	
+++ b/ch04: 集合运算.md	
@@ -1,3 +1,5 @@
+# 第四章：集合运算
+
 # 4.1 表的加减法
 
 ## 4.1.1 什么是集合运算