Fixed README

Formal Languages and Compilers/lesson_02.md

@@ -55,4 +55,4 @@ $$\{ab,bb\}^+ =\{ab,bb,ab^3,b^2ab,abab,b^4,...\}$$
 
 ### Quotient Operator
 It shortens the strings of a language $L'$ by stripping off a *suffix* from another language $L''$
-$$L=L'/L''=\{y|(x=yz\in L')\wedge z\in L''\}$$
+$$L=L'/L''=\{y\|(x=yz\in L')\wedge z\in L''\}$$

README.md

@@ -11,5 +11,5 @@ Subject|completed to|last lesson
 ---|---|---
 Artificial Intelligence | lesson 4|lesson 4
 Data Bases 2|review needed|lesson 2
-Formal Languages and Compilers| lesson 5
+Formal Languages and Compilers| lesson 3 | lesson 5
 Software Engineering 2 | missing content| lesson 4