diff --git a/src/pkg/container/heap/heap.go b/src/pkg/container/heap/heap.go
index 52c8507b42..3fe2327ad2 100644
--- a/src/pkg/container/heap/heap.go
+++ b/src/pkg/container/heap/heap.go
@@ -22,7 +22,7 @@ import "sort"
 // min-heap with the following invariants (established after
 // Init has been called or if the data is empty or sorted):
 //
-//	!h.Less(j, i) for 0 <= i < h.Len() and j = 2*i+1 or 2*i+2 and j < h.Len()
+//	!h.Less(j, i) for 0 <= i < h.Len() and 2*i+1 <= j <= 2*i+2 and j < h.Len()
 //
 // Note that Push and Pop in this interface are for package heap's
 // implementation to call.  To add and remove things from the heap,