diff --git a/sledge/src/fml.ml b/sledge/src/fml.ml
index d47ee1c98..2b49425de 100644
--- a/sledge/src/fml.ml
+++ b/sledge/src/fml.ml
@@ -170,4 +170,27 @@ let map_vars b ~f = map_trms ~f:(Trm.map_vars ~f) b
 
 (** Traverse *)
 
+let fold_pos_neg ~pos ~neg s ~f =
+  let f_not p s = f (not_ p) s in
+  Set.fold ~f:f_not neg (Set.fold ~f pos s)
+
+let fold_dnf ~meet1 ~join1 ~top ~bot fml =
+  let rec add_conjunct fml (cjn, splits) =
+    match fml with
+    | Tt | Eq _ | Eq0 _ | Pos _ | Iff _ | Lit _ | Not _ ->
+        (meet1 fml cjn, splits)
+    | And {pos; neg} -> fold_pos_neg ~f:add_conjunct ~pos ~neg (cjn, splits)
+    | Or {pos; neg} -> (cjn, (pos, neg) :: splits)
+    | Cond {cnd; pos; neg} ->
+        add_conjunct (or_ (and_ cnd pos) (and_ (not_ cnd) neg)) (cjn, splits)
+  in
+  let rec add_disjunct (cjn, splits) fml djn =
+    let cjn, splits = add_conjunct fml (cjn, splits) in
+    match splits with
+    | (pos, neg) :: splits ->
+        fold_pos_neg ~f:(add_disjunct (cjn, splits)) ~pos ~neg djn
+    | [] -> join1 cjn djn
+  in
+  add_disjunct (top, []) fml bot
+
 let vars p = Iter.flat_map ~f:Trm.vars (trms p)
diff --git a/sledge/src/fml.mli b/sledge/src/fml.mli
index 520fb5a18..df8863a54 100644
--- a/sledge/src/fml.mli
+++ b/sledge/src/fml.mli
@@ -67,8 +67,21 @@ val lit : Ses.Predsym.t -> Trm.t array -> t
 val map_vars : t -> f:(Var.t -> Var.t) -> t
 val map_trms : t -> f:(Trm.t -> Trm.t) -> t
 
+val map_pos_neg :
+  (t -> t) -> 'a -> (pos:set -> neg:set -> 'a) -> pos:set -> neg:set -> 'a
+
 (** Traverse *)
 
+val fold_pos_neg : pos:set -> neg:set -> 'a -> f:(t -> 'a -> 'a) -> 'a
+
+val fold_dnf :
+     meet1:(t -> 'conjunction -> 'conjunction)
+  -> join1:('conjunction -> 'disjunction -> 'disjunction)
+  -> top:'conjunction
+  -> bot:'disjunction
+  -> t
+  -> 'disjunction
+
 val vars : t -> Var.t iter
 
 (** Query *)
diff --git a/sledge/src/fol.ml b/sledge/src/fol.ml
index fbeb419cb..b07530db5 100644
--- a/sledge/src/fol.ml
+++ b/sledge/src/fol.ml
@@ -9,9 +9,6 @@ type var = Var.t
 type trm = Trm.t [@@deriving compare, equal, sexp]
 type fml = Fml.t [@@deriving compare, equal, sexp]
 
-let map_pos_neg f e cons ~pos ~neg =
-  map2 (Fml.Set.map ~f) e (fun pos neg -> cons ~pos ~neg) pos neg
-
 (** Conditional terms, denoting functions from structures to values, taking
     the form of trees with internal nodes labeled with formulas and leaves
     labeled with terms. *)
@@ -410,8 +407,8 @@ module Formula = struct
     | Eq0 x -> lift_map1 f b Fml.eq0 x
     | Pos x -> lift_map1 f b Fml.pos x
     | Not x -> map1 (map_terms ~f) b Fml.not_ x
-    | And {pos; neg} -> map_pos_neg (map_terms ~f) b Fml.andN ~pos ~neg
-    | Or {pos; neg} -> map_pos_neg (map_terms ~f) b Fml.orN ~pos ~neg
+    | And {pos; neg} -> Fml.map_pos_neg (map_terms ~f) b Fml.andN ~pos ~neg
+    | Or {pos; neg} -> Fml.map_pos_neg (map_terms ~f) b Fml.orN ~pos ~neg
     | Iff (x, y) -> map2 (map_terms ~f) b Fml.iff x y
     | Cond {cnd; pos; neg} ->
         map3 (map_terms ~f) b
@@ -430,39 +427,6 @@ module Formula = struct
     (e', !s)
 
   let rename s e = map_vars ~f:(Var.Subst.apply s) e
-
-  let fold_pos_neg ~pos ~neg s ~f =
-    let f_not p s = f (Fml.not_ p) s in
-    Fml.Set.fold ~f:f_not neg (Fml.Set.fold ~f pos s)
-
-  let fold_dnf :
-         meet1:('literal -> 'conjunction -> 'conjunction)
-      -> join1:('conjunction -> 'disjunction -> 'disjunction)
-      -> top:'conjunction
-      -> bot:'disjunction
-      -> 'formula
-      -> 'disjunction =
-   fun ~meet1 ~join1 ~top ~bot fml ->
-    let rec add_conjunct fml (cjn, splits) =
-      match fml with
-      | Tt | Eq _ | Eq0 _ | Pos _ | Iff _ | Lit _ | Not _ ->
-          (meet1 fml cjn, splits)
-      | And {pos; neg} ->
-          fold_pos_neg ~f:add_conjunct ~pos ~neg (cjn, splits)
-      | Or {pos; neg} -> (cjn, (pos, neg) :: splits)
-      | Cond {cnd; pos; neg} ->
-          add_conjunct
-            (or_ (and_ cnd pos) (and_ (not_ cnd) neg))
-            (cjn, splits)
-    in
-    let rec add_disjunct (cjn, splits) fml djn =
-      let cjn, splits = add_conjunct fml (cjn, splits) in
-      match splits with
-      | (pos, neg) :: splits ->
-          fold_pos_neg ~f:(add_disjunct (cjn, splits)) ~pos ~neg djn
-      | [] -> join1 cjn djn
-    in
-    add_disjunct (top, []) fml bot
 end
 
 (*