diff -r effb80efba09 -r 93daa824c04a src/convex.rs
--- a/src/convex.rs	Wed Sep 03 14:27:21 2025 -0500
+++ b/src/convex.rs	Wed Sep 03 17:59:24 2025 -0500
@@ -433,7 +433,7 @@
     type Derivative = X::PrincipalV;
 
     fn differential_impl<I: Instance<X>>(&self, x: I) -> Self::Derivative {
-        x.into_owned()
+        x.own()
     }
 }