Make ∖ left associative.

prelude/base.v

@@ -590,7 +590,7 @@ Notation "(∩ x )" := (λ y, intersection y x) (only parsing) : C_scope.
 
 Class Difference A := difference: A → A → A.
 Instance: Params (@difference) 2.
-Infix "∖" := difference (at level 40) : C_scope.
+Infix "∖" := difference (at level 40, left associativity) : C_scope.
 Notation "(∖)" := difference (only parsing) : C_scope.
 Notation "( x ∖)" := (difference x) (only parsing) : C_scope.
 Notation "(∖ x )" := (λ y, difference y x) (only parsing) : C_scope.

program_logic/namespaces.v

@@ -77,7 +77,7 @@ Section ndisjoint.
 End ndisjoint.
 
 (* The hope is that registering these will suffice to solve most goals
-of the form [N1 ⊥ N2] and those of the form [((N1 ⊆ E ∖ N2) ∖ ..) ∖ Nn]. *)
+of the form [N1 ⊥ N2] and those of the form [N1 ⊆ E ∖ N2 ∖ .. ∖ Nn]. *)
 Hint Resolve ndisj_subseteq_difference : ndisj.
 Hint Extern 0 (_ ⊥ _) => apply ndot_ne_disjoint; congruence : ndisj.
 Hint Resolve ndot_preserve_disjoint_l : ndisj.