diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index 2cb122a..1c964f2 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -1967,7 +1967,7 @@ bool checkMaxBetweenExclusive(Node *n, int begin, int end,
                               InternalVersionT readVersion) {
   assume(-1 <= begin);
   assume(begin <= 256);
-  assume(0 < end);
+  assume(-1 <= end);
   assume(end <= 256);
   assume(begin < end);