diff --git a/src/smt/seq/seq_nielsen_pp.cpp b/src/smt/seq/seq_nielsen_pp.cpp
index f4faa67ea..a0b54dd60 100644
--- a/src/smt/seq/seq_nielsen_pp.cpp
+++ b/src/smt/seq/seq_nielsen_pp.cpp
@@ -159,7 +159,7 @@ namespace seq {
         }
         if (m.is_not(e, x))
             return "!(" + arith_expr_html(x, names, next_id, m) + ")";
-        if (arith.is_le(e, x, y)) {
+        if (arith.is_lt(e, x, y)) {
             return arith_expr_html(x, names, next_id, m) + " < " + arith_expr_html(y, names, next_id, m);
         }
         if (arith.is_gt(e, x, y)) {