diff -r 402d717bb5c0 -r 829c07ea584d src/instance.rs
--- a/src/instance.rs	Mon Sep 01 20:55:34 2025 -0500
+++ b/src/instance.rs	Mon Sep 01 23:08:01 2025 -0500
@@ -186,7 +186,8 @@
 /// generalises [`std::borrow::ToOwned`], [`std::borrow::Borrow`], and [`std::borrow::Cow`].
 ///
 /// This is used, for example, by [`crate::mapping::Mapping::apply`].
-pub trait Instance<X, D = <X as Space>::Decomp>: Sized + Ownable
+pub trait Instance<X, D = <X as Space>::Decomp>:
+    Sized + Ownable<OwnedVariant = X::OwnedSpace>
 where
     X: Space,
     D: Decomposition<X>,