Typo

Author: eliasdiem

ch12/12.7/12.7.md

@@ -1,4 +1,4 @@
-# 12.7 Exercises for Section 12.7
+# Exercises for Section 12.7
 
 ### 12.7.1
 
@@ -12,15 +12,17 @@
 ### 12.7.2
 
 #### answer
+
 For each variable, we put it on one layer. Their is only two possible arrangement left 0 or left 1. So for each variable, we need at most two nodes for it. And we need only one node for the first variable. So the answer is:  
 *2n-1*  
 For example, when n is 4:  
 ![12.7.2](https://raw.github.com/fangang190/dragon-book-exercise-answers/master/ch12/12.7/assets/12.7.2.png)
 
 ### 12.7.3
+
 #### answer
 
 There are two places to modify:  
 
 a. BASIS: Zero variables. The BDD's must both be leaves, labeled either 0 or 1. The output is the leaf labeled 1 if `both` input are 1, or the leaf labeled 0 if `either` is 0.  
-b. INDEUCTION 2. ...The first of these BDD's represents the function that is true for all truth assignments that have y<sub>1</sub> = 0 and that make `both` of the give BDD's true.
+b. INDEUCTION 2. ...The first of these BDD's represents the function that is true for all truth assignments that have y<sub>1</sub> = 0 and that make `both` of the give BDD's true.