diff -r d8305c9b6fdf -r f7b87d84864d src/bisection_tree/aggregator.rs
--- a/src/bisection_tree/aggregator.rs	Sat Dec 21 23:32:20 2024 -0500
+++ b/src/bisection_tree/aggregator.rs	Sun Dec 22 14:54:46 2024 -0500
@@ -4,6 +4,7 @@
 
 use crate::types::*;
 use crate::sets::Set;
+use crate::instance::Instance;
 
 /// Trait for aggregating information about a branch of a [bisection tree][super::BT].
 ///
@@ -136,10 +137,11 @@
 }
 
 impl<F : Float> Set<F> for Bounds<F> {
-    fn contains(&self, item : &F) -> bool {
+    fn contains<I : Instance<F>>(&self, item : I) -> bool {
+        let v = item.own();
         let &Bounds(l, u) = self;
         debug_assert!(l <= u);
-        l <= *item && *item <= u
+        l <= v && v <= u
     }
 }