Update README.md

README.md

 # General lab info
 
+```math
+\frac{\lang c_1,\sigma \rang \longrightarrow \sigma' \qquad \lang c_2, \sigma \rang \longrightarrow \sigma'}
+{\lang c_1; c_2;,\sigma \rang \longrightarrow \sigma''} 
+```
+
 In this course you will use Git extensively. To master Git and/or similar content management system with version control is absolutely essential engineering skill. If you have not used Git or similar, here is your chance to learn.
 
 If you are under Linux, you likely have Git installed by default (else use your Linux package manager to install it). If you are under Windows, then look at https://git-scm.com/downloads. If you get stuck, use the Telegram group to ask questions and help each other out.