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+(* How to prove a sample theorem by PBP. *)
+
+(* All using middle-clicks.
+  
+   1. Click on  ->        (Intros A B)
+   2. Click on  -> again  (Intros H; Try Refine H)
+   3. Click on A          (Intros H1; Try Refine H1)
+   4. Click on B          (Intros H2; Try Refine H2)
+   5. Click on A in A/\B  (Refine pair; Try Assumption)
+   6. Click on final B    (Try Assumption)
+   QED!!
+*)
+
+Module pbp Import lib_logic;
+
+Goal {A,B:Prop}(A /\ B) -> (B /\ A);
+Intros A B; 
+Intros H; Try Refine H; 
+Intros H1; Try Refine H1; 
+Intros H2; Try Refine H2; 
+Refine pair; Try Assumption; 
+Try Assumption; 
+Save and_comms;
+
+
+
+
+