diff --git a/theories/base.v b/theories/base.v
index 22752705fcfc727038368eb0053fb2d86e83e8c3..bfcb09aed3bd222aa10776452726f0578050b795 100644
--- a/theories/base.v
+++ b/theories/base.v
@@ -637,6 +637,11 @@ Notation "(⊄)" := (λ X Y, X ⊄ Y) (only parsing) : C_scope.
Notation "( X ⊄ )" := (λ Y, X ⊄ Y) (only parsing) : C_scope.
Notation "( ⊄ X )" := (λ Y, Y ⊄ X) (only parsing) : C_scope.
+Notation "X ⊆ Y ⊆ Z" := (X ⊆ Y ∧ Y ⊆ Z) (at level 70, Y at next level) : C_scope.
+Notation "X ⊆ Y ⊂ Z" := (X ⊆ Y ∧ Y ⊂ Z) (at level 70, Y at next level) : C_scope.
+Notation "X ⊂ Y ⊆ Z" := (X ⊂ Y ∧ Y ⊆ Z) (at level 70, Y at next level) : C_scope.
+Notation "X ⊂ Y ⊂ Z" := (X ⊂ Y ∧ Y ⊂ Z) (at level 70, Y at next level) : C_scope.
+
(** The class [Lexico A] is used for the lexicographic order on [A]. This order
is used to create finite maps, finite sets, etc, and is typically different from
the order [(⊆)]. *)