enduser/Modal-Transition-Systems.md

-Modal transition systems (MTS) can be modelled by using a question mark (?) on event labels.
+# Modal Transition Systems
+
+Modal transition systems (MTS) can be modelled by using a question mark (`?`) on event labels to indicate may-transitions (transitions that may or may not be present in an implementation).
+
 ```
 A = (a -> b? -> A | a? -> A).
 ```
 
 # Abstract keyword
-The abstract keyword builds an MTS from a FSP process adding to each state maybe
-transitions on labels that are not enabled in the original process.
+The `abstract` keyword builds an MTS from an FSP process by adding to each state maybe-transitions on labels that are not enabled in the original process.
 It can be applied both to sequential and composite processes.
 
 ```
@@ -15,7 +17,5 @@ B = (a -> b -> B | b? -> B).
 abstract ||COMP = (B).
 ```
 
-# End
-
 ---
-[← End User](End-User)
\ No newline at end of file
+[← End User](End-User)