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diff --git a/Source/Jennisys/examples/BHeap.jen b/Source/Jennisys/examples/BHeap.jen
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+interface BHeap {
+  var elems: set[int]
+
+  constructor Singleton(x: int)
+    ensures elems = {x}
+
+  constructor Dupleton(a: int, b: int)
+    requires a != b
+    ensures elems = {a b}
+
+  constructor Tripleton(x: int, y: int, z: int)
+    requires x != y && y != z && z != x
+    ensures elems = {x y z}
+
+  method Find(n: int) returns (ret: bool)
+    ensures ret = (n in elems)	
+}
+
+datamodel BHeap {
+  var data: int
+  var left: BHeap
+  var right: BHeap
+
+  frame 
+    left * right
+
+  invariant
+    elems = {data} + (left != null ? left.elems : {}) + (right != null ? right.elems : {})
+    left != null  ==> forall e :: e in left.elems ==> e < data
+    right != null ==> forall e :: e in right.elems ==> e < data
+	left = null ==> right = null
+	(left != null && right = null) ==> left.elems = {left.data}
+}