Add use info to README.md

README.md

@@ -60,6 +60,53 @@ that map to true and false, respectively.
 Usage
 -------
 
+Peregrine is run from the command line. 
+
+If you save the protocol from above in the file *majority.pp* and enter:
+```bash
+    peregrine majority.pp
+```
+
+You obtain the following output:
+```
+Peregrine - Efficient Verification of Population Protocols
+
+Reading "majority.pp"
+Analyzing Population protocol "Majority Protocol"
+
+Checking layered termination
+Checking layered termination with at most 1 layers
+Checking layered termination with at most 2 layers
+layered termination satisfied
+
+Checking strong consensus
+strong consensus satisfied
+
+All properties satisfied
+```
+
+As seen in the output, Peregrine by default checks two properties: 
+*Layered Termination* and *Strong Consensus*:
+
+* Layered Termination: every fair run of the protocol
+will eventually reach a terminal population where no more change occurs.
+* Strong Consensus: every terminal population reachable from an initial population
+  forms a consensus. Moreover, the boolean value of the consensus must be unique 
+  for a given initial population.
+
+If both Layered Termination and Strong Consensus are satsified, then the protocol
+is *well-specified*, i.e. the protocol robustly computes a predicate defined
+by the mapping from input population to its unique consensus value.
+Note that the converse direction need not hold: there are well-specified protocols
+that violate the conjunction of Strong Consensus and Layered Termination.
+
+Peregrine offers fine-grained control over the solution methods and the 
+verbosity of the output.
+To see all options, enter:
+```bash
+    peregrine --help
+```
+
 Authors
 -------