diff -r 03f34ba55685 -r 45d03cf92c23 src/instance.rs
--- a/src/instance.rs	Mon Sep 01 23:08:27 2025 -0500
+++ b/src/instance.rs	Tue Sep 02 00:05:29 2025 -0500
@@ -144,6 +144,9 @@
 
 /// Marker type for decompositions to be used with [`Instance`].
 pub trait Decomposition<X: Space>: Sized {
+    /// Owned instance
+    type OwnedInstance: Instance<X, Self>;
+
     /// Possibly owned form of the decomposition
     type Decomposition<'b>: Instance<X, Self>
     where
@@ -156,8 +159,11 @@
     where
         X: 'b;
 
-    /// Left the lightweight reference type into a full decomposition type.
+    /// Lift the lightweight reference type into a full decomposition type.
     fn lift<'b>(r: Self::Reference<'b>) -> Self::Decomposition<'b>;
+
+    // /// Lift the lightweight reference type into a fully owned type
+    // fn full_lift<'b>(r: Self::Reference<'b>) -> Self::OwnedInstance;
 }
 
 /// Most common [`Decomposition`] (into `Either<X, &'b X>`) that allows working with owned
@@ -165,7 +171,9 @@
 #[derive(Copy, Clone, Debug)]
 pub struct BasicDecomposition;
 
-impl<X: Space> Decomposition<X> for BasicDecomposition {
+impl<X: Space + Clone> Decomposition<X> for BasicDecomposition {
+    type OwnedInstance = X;
+
     type Decomposition<'b>
         = MyCow<'b, X>
     where
@@ -207,14 +215,14 @@
         Self: 'b;
 
     /// Returns an owned instance of `X`, cloning or converting non-true instances when necessary.
-    fn own(self) -> X;
+    fn own(self) -> D::OwnedInstance;
 
     // ************** automatically implemented methods below from here **************
 
     /// Returns an owned instance or reference to `X`, converting non-true instances when necessary.
     ///
     /// Default implementation uses [`Self::own`]. Consumes the input.
-    fn cow<'b>(self) -> MyCow<'b, X>
+    fn cow<'b>(self) -> MyCow<'b, D::OwnedInstance>
     where
         Self: 'b,
     {
@@ -225,7 +233,7 @@
     /// Evaluates `f` on a reference to self.
     ///
     /// Default implementation uses [`Self::cow`]. Consumes the input.
-    fn eval<'b, R>(self, f: impl FnOnce(&X) -> R) -> R
+    fn eval<'b, R>(self, f: impl FnOnce(&D::OwnedInstance) -> R) -> R
     where
         X: 'b,
         Self: 'b,
@@ -237,7 +245,11 @@
     /// Evaluates `f` or `g` depending on whether a reference or owned value is available.
     ///
     /// Default implementation uses [`Self::cow`]. Consumes the input.
-    fn either<'b, R>(self, f: impl FnOnce(X) -> R, g: impl FnOnce(&X) -> R) -> R
+    fn either<'b, R>(
+        self,
+        f: impl FnOnce(D::OwnedInstance) -> R,
+        g: impl FnOnce(&D::OwnedInstance) -> R,
+    ) -> R
     where
         Self: 'b,
     {
@@ -248,7 +260,7 @@
     }
 }
 
-impl<X: Space> Instance<X, BasicDecomposition> for X {
+impl<X: Space + Clone> Instance<X, BasicDecomposition> for X {
     #[inline]
     fn eval_decompose<'b, R>(self, f: impl FnOnce(MyCow<'b, X>) -> R) -> R
     where
@@ -281,7 +293,7 @@
     }
 }
 
-impl<'a, X: Space> Instance<X, BasicDecomposition> for &'a X {
+impl<'a, X: Space + Clone> Instance<X, BasicDecomposition> for &'a X {
     #[inline]
     fn eval_decompose<'b, R>(self, f: impl FnOnce(MyCow<'b, X>) -> R) -> R
     where
@@ -302,7 +314,7 @@
 
     #[inline]
     fn own(self) -> X {
-        self.into_owned()
+        self.clone()
     }
 
     #[inline]
@@ -314,7 +326,7 @@
     }
 }
 
-impl<'a, X: Space> Instance<X, BasicDecomposition> for &'a mut X {
+impl<'a, X: Space + Clone> Instance<X, BasicDecomposition> for &'a mut X {
     #[inline]
     fn eval_decompose<'b, R>(self, f: impl FnOnce(MyCow<'b, X>) -> R) -> R
     where
@@ -335,7 +347,7 @@
 
     #[inline]
     fn own(self) -> X {
-        self.into_owned()
+        self.clone()
     }
 
     #[inline]
@@ -347,7 +359,7 @@
     }
 }
 
-impl<'a, X: Space> Instance<X, BasicDecomposition> for MyCow<'a, X> {
+impl<'a, X: Space + Clone> Instance<X, BasicDecomposition> for MyCow<'a, X> {
     #[inline]
     fn eval_decompose<'b, R>(self, f: impl FnOnce(MyCow<'b, X>) -> R) -> R
     where