diff --git a/sledge/src/trm.ml b/sledge/src/trm.ml
index 693d035f9..f68ed9355 100644
--- a/sledge/src/trm.ml
+++ b/sledge/src/trm.ml
@@ -386,6 +386,15 @@ end = struct
   let vars e = Iter.from_labelled_iter (iter_vars e)
 end
 
+module T = struct
+  type t = Trm.t [@@deriving compare, sexp]
+end
+
+module Map = struct
+  include Map.Make (T)
+  include Provide_of_sexp (T)
+end
+
 type arith = Arith.t
 
 include Trm
diff --git a/sledge/src/trm.mli b/sledge/src/trm.mli
index 5fd7dcafe..745e53ea6 100644
--- a/sledge/src/trm.mli
+++ b/sledge/src/trm.mli
@@ -41,6 +41,12 @@ end
 module Arith :
   Arithmetic.S with type var := Var.t with type trm := t with type t = arith
 
+module Map : sig
+  include Map.S with type key := t
+
+  val t_of_sexp : (Sexp.t -> 'a) -> Sexp.t -> 'a t
+end
+
 val ppx : Var.strength -> t pp
 val pp : t pp
 val pp_diff : (t * t) pp