diff -r 016122e0384b -r 30af49ae2135 src/linops.rs
--- a/src/linops.rs	Tue Aug 04 14:53:58 2026 -0500
+++ b/src/linops.rs	Sun Aug 23 22:12:08 2026 -0500
@@ -36,7 +36,7 @@
     + Add<Self::PrincipalV, Output = Self::PrincipalV>
     + Sub<Self, Output = Self::PrincipalV>
     + Sub<Self::PrincipalV, Output = Self::PrincipalV>
-    + Neg
+    + Neg<Output = Self::PrincipalV>
     + for<'b> Add<&'b Self, Output = <Self as VectorSpace>::PrincipalV>
     + for<'b> Sub<&'b Self, Output = <Self as VectorSpace>::PrincipalV>
 {